Git Rot?

[Carl Stone]

I have a few planks (cedar) that were damaged over the years from fresh water (refridgerator drain)and are black and about 50% erroded. Not large areas, but enough to want to restore them. In water is the only way, so your opinions please...I have never used Git Rot..does it perform as advertised, or is straight epoxy as effective. The planks are below the water line, and slightly damp most of the time, but a heat lamp can dry them out. Would this product work on my one soft hardwood frame as well?

[Kings cruiser]

Hull out.
it would be very very hard to dry that area up enough to make the glue/or whatever count. i'd kill it with salt, and then attempt to lever the boat to one side for an extended period of time with lamp, etc... and even then, by virtue of water's dialatory ways, it'd probably be a pain.. i've had enough trouble fixing a similar problem on deck/cabin during the San Francisco summer (foggy..sunny)/
hull out.

[Ian McColgin]

CPES works better than GitRot - check the 'Rot Doctor' for propaganda to be taken with some grains of salt.

It's generally easier and faster to chissel out rot and put in a dutchman.

Generally trying trying to dry and then epoxysaturate the rot, plus saturate ahead of it so it won't spread it hard and doesn't usually work so you just move the rot ahead faster, but as a desperation measure it is just within the outer bounds of possibility.

CPES is so toxic to all life forms that I see utterly no point in other 'rot antidotes', especially such gentle ones as salt.

Er . . . G'luck

[NormMessinger]

Hmmm. Don't know anyting about getrot. CPES may penetrate and kill but it wont consolidate, it's mostly slovent. System Three has a product in their catalogue now which may work for you. SOunds as if it is as unviscous as CPES but lacks solvent so will completely consolidate the substrate. Only know what SysThree says about it in this regard however.

--Norm

[thechemist]

It might be represented in the comparison tests on the RotDoctor web site.

[Bob Cleek]

The problem with epoxy saturation of rotten wood is that the rot spores always penetrate (i.e. infect) the wood far deeper than the epoxy ever will. So the rot is always a few steps ahead of you. It's like cancer. Chemo only works AFTER surgery! LOL If your plank is half eaten up, as you say, you are better off (cheaper in the long run, too) pulling the plank and replacing it completely. Same for the punk frame. Fix the leaky drain on your ice box while you are at it!

[Mike Keers]

These guys are right about how far rot can spread. Just a few hours ago I cut up a salvaged fir 2x6 that had a bit of punk, a spot about the size of a quarter on one end. There was a tunnel of dry punky wood, and I mean a space you can look thru, that extended the entire ten feet of the board, yet the outside faces were perfect, clear VG wood. If you knew where to poke, you could put your finger right thru the entire board. I've seen this many times.

[Dave Carnell]

The trouble with epoxies highly diluted with solvent, such as CPES and Git-Rot is that the solvent evaporates after the epoxy cures, leaving a veritable sponge structure.

System Three's Ror-Fix appears from the MSDS sheet to be on the right track. It is epoxy diluted with reactive solvent; e.g., butyl glycidyl ether, so that it is a 100% solids system and cures to a solid. It is not water-miscible, so will not penetrate wet wood farther than the solvent-based products.

Ethylene glycol auto antifreeze will penetrate the farthest reaches of wood given enough application and time. This is because glycol has an voracious thirst for water unmatched by any common compound.

For example, laboratory workers use dessicators to keep samples bone dry. Common dessicants used to maintain the superdry environment are materials such as phosphorus pentoxide and fuming sulfuric acid. In Chemical Abstracts back when ethylene glycol was first produced as an industrial compound in the 1920s I found a paper in which a researcher demonstrated that glycol was a more powerful dessicant than either of the compounds named above.

I put an open container of glycol in my shop to measure its evaporation rate back when I began working with glycol as a wood stabilizing agent, as for archaeological wood, before I recognized its effectiveness in killing rot organisms. Instead of losing weight by evaporation, the container gained weight fairly rapidly asit absorbed water from the atmosphere until the glycol weight was about 50% greater than at the start.

Also, because of its similarity to water, glycol is most strongly absorbed by wood.

Add its demonstrated toxicity to organisms from bacteria and molds to humans and you can see why it is so effective in stopping rot.

It does absolutely nothing to rebuild the structure of the rotted wood, but it prepares a way for low-viscosity epoxy to penetrate better the rotted wood and strengthen it.

The System Three approach of diluting with reactive solvent has to be far superior to CPES, which contains so little epoxy it does not have to be listed as a hazardous ingredient on the MSDS.

Recently I discovered a rotted spot the size of a dime or less in the edge of the pl;ywood side deck of my Simmons Sea-Skiff. I flooded it with antifreeze. After a few days the spongy, wet mass was dry and crumbly. How could this be?

This was such a small rotted area and I flooded it with such an excess of glycol that when the glycol migrated into the adjacent sound wood it also absorbed the water in the rotted wood and carried it into the sound wood.

I had a lovers' knot rope mat at our back door. It is exposed to the rain and often wet. After a couple of years the coir fiber rotted to mush, literally.

After I spent $25 at West Marine to replace it, I thoroughly paintedthe new mat with antifreeze. After about eight years, it shows no sign of deterioration.

The persistence of protection from rot provided by glycol even though it is water-soluble can be explained by the fact that the attraction between cellulose and glycol is stronger than between water and glycol, so it is retained sufficiently when wet to prevent rot for a long time. I have observed this effect in rotted areas in wood on boats.

I have no involvement with the glycol industry. I cannot sell glycol for rot cure because I don't have an EPA registration for it for that purpose. No company is going to spend the money to get an EPA registration because the potential market is a fart in a whirlwind compared to the major uses as an ingredient of polyester plastics, fibers, and films and as antifreeze. If a company had EPA registration, anyone else could piggyback on it for free, as the various sellers of sodium octaborate products get a free ride on U.S. Borax's EPA registration of the product, but they have to buy the sodium octaborate from U.S. Borax.

All I can do is give away what I have learned for anyone to use as they see fit. That is all right; I have attained 80 years and there is satisfaction in giving away useful knowledge. Use it as you see fit.

[Scott Rosen]

I just read the "new and improved" rot doctor site, which has an interesting comparison of the penetration of these various products. While it's true that CPES does not have the strength of a less-diluted epoxy, it has much, much better penetration. The System Three product may be strong, but if it doesn't penetrate fully, what's the point? Rot doc advocates a two-step process. First penetrate and stabilize with CPES. Then if necessary saturate with a low-viscocity epoxy for strength. This method appears (at least on my reading) to address the weaknesses of using either CPES or unthinned epoxy alone.

It's worth a read. www.rotdoctor.com The experiment is very simple and easy to understand, with photos showing the results.

[paul oman]

I have tested both Git Rot and CPES in my penetrating epoxy tests (www.epoxyproducts.com/penetrating4u.html)

CPES is of the massive solvent school. Git Rot is of the low viscosity school.

I like the middle road - start with a low viscosity epoxy and thin about 10% with xyelene or similar solvent.

I think Dave is on the money with the anti-freeze approach. Use that - let 'dry' then epoxy coat. There are epoxies that will stick to water saturated surfaces - this might or might not improve the epoxy to anti-freeze bond.

paul

[thechemist]

Unnnnhhh...paul....Viscosity means "resistance to flow".......and CPES runs almost like water...flows more easily by far than Git-Rot......I think you misspoke:

Originally posted by paul oman:
I have tested both Git Rot and CPES in my penetrating epoxy tests (www.epoxyproducts.com/penetrating4u.html)

CPES is of the massive solvent school. Git Rot is of the low viscosity school.

Perhaps what you meant to say was that Git-Rot had a higher solids content than CPES, but CPES had a lower viscosity, meaning consequently it penetrated more easily, deeply, quickly, etcetera. I am not in a position to debate what "works" better, although the penetration tests on the Rot Doctor's web site are informative.

The issue of epoxy compatibility with glycol-impregnated wood is an interesting one, and there is good reason to be suspicious of the interface between the epoxy and the glycol-impregnated wood, where the epoxy might absorb an unknown and excessive amount of ethylene glycol. For a study of epoxy degradation by ethylene glycol with water exposure, see

http://media5.hypernet.com/~dick/ubb...ML/002241.html

Different application circumstances are likely to give different results, and what is found satisfactory by one user may, in another more demanding circumstance be found lacking, or even lead to a time-delayed disaster.

This is a good reason for users to do their own tests on pieces of wood treated invarious ways, and soak them in warm water for a month and do other things, and observe for themselves what really works.

I only tested two different epoxy systems in the aforementioned study, and it is certain that different epoxy systems, in combination with different woods in different states of decay [if any] will give results varying from perhaps no observable change to disastrous.

I would remind all the readers of this forum that ethylene glycol [or the crude industrial blend marketed as vehicle antifreeze] is vastly less expensive than the ingredients used in commercial epoxy products, and if any manufacturer thought they could get away with adding some antifreeze to an epoxy formulation, they would do it, for it would mean additional profit at no expense.

They do not do this.

There must be a reason......and the aforementioned study gives a good clue.

Paul, I doubt even you add antifreeze to the formulations you make and sell yourself. It would mean an additional profit......so why don't you do it?

[Dave Carnell]

Adding ethylene glycol to epoxy is no way to deliver it to the rotting wood site. Gougeon has published a paper on the effects of ethylene glycol and glycol-borate solutions on epoxy adhesion to pine and white oak. Only the glycol-borate solutions caused significant weakening of the joint strength.

Treat with glycol first and then use your epoxy filler.

All the rot doctor tests are on dry balsa wood. There is no test of penetration of wet wood, as in rot cure situations. CPES has a fair amount of water-soluble solvents in its mixture, which might be reasoned to give better penetration of wet wood. However, the first drop of water added to mixed CPES causes a second phase to separate, which makes you wonder about penetration of wet wood. Nothing begins to penetrate wet wood as ethylene glycol does.

Non-anonymous
Dave Carnell
322 Pages Creek Drive
Wilmington, NC 28411-7850

[Dave Carnell]

I knew you'd ask!

The Effect of Ethylene Glycol and Sodium Borate Solutions on the
Adhesion of Epoxy to White Oak and White Pine Samples.

Dan Freel, Chris Maples, Bruce Niederer,
William T. (Chip) Reynolds, and James R. Watson


Abstract

The search for low toxicity wood preservatives results in the use of products that may affect the adhesion of finishes and glues
in wood construction. Ethylene glycol and sodium borate are two such products that have been used singly and in combination
for their fungicidal qualities. This paper reports the results of tests of solutions of these compounds in varying concentrations.
Results indicate that a 75% ethylene glycol/25% sodium borate solution has a marked detrimental effect on the adhesion of
epoxy to white oak, and to a lesser extent reduces adhesion of epoxy to white pine. Other concentrations of ethylene glycol
and water increase adhesion of epoxy to wood substrates. Recommendations are provided for the use of WEST SYSTEM(R)
105/206 epoxy on white oak and white pine that has been treated with various concentrations of these solutions.

Introduction

With the heightened environmental awareness of today's society, both professional and amateur boat builders and restorers
have begun searching for wood preservatives of minimal environmental and occupational safety impact. Wood preservatives of
relatively high toxicity have been in use for decades, as a prophylactic in new construction and as a remedial treatment in repair
and reconstruction. The effect of such preservatives on adhesion of finishes and glues is reasonably well known.

Both sodium borate and ethylene glycol solutions have been promoted as low toxicity preservatives for use in timber frame
construction and marine applications, and as low toxicity fungicides and termaticides. The efficacy and limitations of these
solutions in preventing wood deterioration is well documented. However, other than anecdotal experiences and the assurances
of producers, little information documents the effects of ethylene glycol and sodium borate solutions on the adhesion of finishes
and glues.

The Gougeon Brothers lab has adhesion data from seven years of standardized testing of various wood and epoxy
combinations. Tests have included the use of WEST SYSTEM(R) epoxies as both adhesives and coatings. Relevant to the
instant experiment, in 1991 Gougeon Brothers tested the effects of oil based, alcohol based and water based stains on the
adhesion of epoxy coatings. These tests indicated that with oil based stains adhesion can be seriously jeopardized, while
adhesion is satisfactory with alcohol and water based stains.

This paper relates the results of a preliminary test of WEST SYSTEM(R) 105/206 epoxy adhesion to substrates of white oak
and white pine treated with solutions containing varying concentrations of ethylene glycol, sodium borate, or both. While the
results described below are promising for the use of certain solutions in combination with WEST SYSTEM(R) 105/206 as a
bonding or coating agent, further testing is needed to better report definitive effects on adhesion and bonding strength.

Methodology

The Pneumatic Adhesion Tensile Testing Instrument (PATTI) manufactured by SEMicro Corporation is the standard instrument
used by Gougeon Brothers to determine the adhesion strength of epoxies on various substrates. In addition to internal
standardization within Gougeon Brothers labs, the PATTI conforms to the American Society for Testing and Materials
'Standard for Pull-off Strength of Coatings Using Portable Adhesion Testers' ASTM Standard D 4541-85(89). The ASTM
standard provides the procedure used by Gougeon Brothers to determine adhesion strength of epoxies on various substrates.

Lengths of 1"X6" white pine and white oak panels served as the substrate for testing to provide an indication of adhesion in soft
wood and hard wood. The panels received one of five treatments, listed below.

#Control - no treatment provided.
#75% ethylene glycol / 25% sodium borate
#50% (75% ethylene glycol/25% sodium borate) / 50% water
#50% ethylene glycol / 50% water
#100% ethylene glycol

Within each treatment group the panels were tested. Each solution was applied to the flat of the test panel by hand with a small
paint brush to ensure maximum absorption. The panels dried at room temperature for three days prior to bonding the PATTI
studs.

In summary, the PATTI applies an aligned and controlled force, applied by pneumatic pressure, to an aluminum cylinder (called
the 'stud') attached to the surface being tested, until reaching a maximum force or failure. The PATTI provides a gauge that
translates the pneumatic force into pounds per square inch of force. The attachment of the stud is controlled to ensure strict
conformity between samples. The stud, about _" in diameter, is etched with WEST SYSTEM(R) 860 two step etching solution
prior to bonding, then bonded to the surface being tested with the requisite epoxy, and allowed to cure appropriately. In this
instance, WEST SYSTEM(R> 105/206 was used as the bonding agent, and allowed to cure at room temperature for two days
prior to testing.

Test Results

Test results for the samples are presented as the average value of the three samples within each treatment group. The data
present both the pounds per square inch (p.s.i.) of force applied at failure, and the percent of wood failure within the area of
bonding (at increments of 5%). These measures provide both a quantitative measurement for comparison and a qualitative
sense of the integrity of the bond.


Solution applied
Adhesion p.s.i. at failure
% Wood failure
White Oak


1.
Control
1625
68
2.
75% e. glycol/25% s. borate
579
10
3.
50% (75% / 25%)/50% water
1285
48
4.
50% e. glycol/50% water
1774
80
5.
100% e. glycol
1380
38
White Pine


1.
Control
661
100
2.
75% e. glycol/25% s. borate
511
100
3.
50% (75% / 25%) /50% water
620
100
4.
50% e. glycol /50% water
701
100
5.
100% e. glycol
756
100


Discussion and Conclusions

The results presented herein cannot be viewed as definitive, but do provide good illustration of certain areas where the ethylene
glycol and or sodium borate may be appropriately used. This test examined only white oak and white pine, and while indicative
of the results that may be found in other woods, one cannot extrapolate with confidence from these results to other woods.

Certain results also do not lend themselves to an intuitive explanation. For example, many plausible reasons could be presented
for increased adhesion under certain test solutions, but none can be validated based on the results presented herein.

We have no explanation for why the 75% ethylene glycol/25% sodium borate solution results in such diminished adhesion, on
both the soft and hard wood. A better understanding of this phenomenon requires further testing, with particular attention to the
testing of various sodium borate solutions alone and in combination with ethylene glycol. It may be that the sodium borate
leaves a residue that affects adhesion, but this interpretation is speculative.

Further testing of the 75%/25% solution would be of value, given that some recommend the use of these two chemical additives
in common to attain greater penetration of the wood treated (due to the effect of the ethylene glycol) and longer lasting
preservative qualities (due to the effect of the sodium borate). Indeed, certain proprietary products tout the benefits of this
combination of preservatives.

Even in the absence of statistical analysis, it is clear that application of the 75% ethylene glycol/25% sodium borate solution
results in a significant loss of adhesion. This is especially true with the white oak substrate, where the loss of adhesion is
sufficient to jeopardize bonding for structural purposes. The minimal wood failure with the 75%/25% solution and white oak
substrate also calls into question the applicability of this combination even for applications limited to coatings.

With any but the 75%/25% solution and white oak, one may safely use WEST SYSTEM 105/206 for coating applications. On
white oak treated with the 50% e. glycol/50% water solution, one may safely use WEST SYSTEM 105/206 for bonding
applications.

The situation with respect to the white pine is less definitive. The loss of adhesion under the 75%/25% solution is less dramatic
than with the white oak, and the white pine still shows 100% wood failure. Even so, in structural bonding applications one
would be wise to adopt a conservative approach and avoid using the 75%/25% solution. With any of the solutions and white
pine, one may safely use WEST SYSTEM 105/206 for coating. With any but the 75%/25% solution and white pine, one may
safely use WEST SYSTEM 105/206 for bonding applications.

Given the differing bonding and solution absorbing characteristics of various wood substrates, it is unwise to extrapolate from
these results to other woods. Those interested in using sodium borate or ethylene glycol solutions as preservatives in
combination with other woods are advised to test samples with the solution to be used.

Gougeon Brothers, Inc.
WEST SYSTEM Epoxies
P.O. Box 908
Bay City, MI 48707-0908
517/684-7286

Return to the Preservation Conference Schedule page.
Return to the Maritime Park Association home page.

Copyright (C) 1997, Maritime Park Association.
All Rights Reserved.
Version 1.01, 7 July 1997