Veneer Questions

[redwoodwing]

Greetings all! Speaking of the chemist.....

I have a gorgeous piece of crotch veneer that I need to flatten as it is going to be the outside of the transom...the veneer is approximately 4'x2.5'....
very wavy, but no voids or cracks as of yet.
I have researched it to understand that a typical formula for flattening veneer is the use of a mix of water, alcohol and glycerin.
I emailed west system to make certain that the glycerin would not be a problem with epoxy when i go to attach it to the transom ply..
alas, they recommend against it, as combinations go.

So I turn to the greater "you" for much needed help.....
do I just use water and gently increasing pressure, ...letting it slowly dry with paper ..under pressure?

Thanks in advance for your help!
Jane

[Bob Smalser]

There is a veneer softener called GF-20 commercial outfits use to soften and press veneer. It's a glycol ether and not a sugar alcohol like glycerine. It's popular because it allows the veneers to quickly dry back down to moisture contents suitable for gluing.

http://www.veneersystems.com/images/products/H11-thumb-200.gif

http://www.veneersystems.com/

I'd call them and ask what glues it is compatible with, and I'd pose the glue compatibility question on woodweb for additional verification from those who use it regularly.

http://www.woodweb.com

[redwoodwing]

Bob-
Thanks for the pointers! I emailed veneer systems, and their reply was that it "should" be fine. I've posted on woodweb...but so far no responses. (and i've googled this issue twelve ways from sunday with no luck). I also wrote west system again, posing this new chemistry question..they did mention that they intended to do new tests with glycerine shortly, so perhaps they will do trials with the GF 20 as well. I will, when all is said and done - post the final responses from the vendors as well as what my decision is for the lay up....of course I will test on scrap first, and post the "obvious to the lay eye" results.

[Bob Smalser]

...I've posted on woodweb...but so far no responses. (and i've googled this issue twelve ways from sunday with no luck)....

Probably because the commercial folks are all furniture makers who veneer with UF resin or a commercial aliphatic. Remember the manufacturer words responses to avoid liability. I don't think traces of glycol residue will interfere with an epoxy bond, and the ether evaporates completely. Do a search here in B&R on using ethylene glycol as a rot preventative and ask those builders if they are gluing their treated wood successfully.

I'd also ask around any speedboat/runabout forums. I'm sure there are builders of new mahogany runabouts today on the Great Lakes and elsewhere using veneers that require pressing.

[carioca1232001]

There is a veneer softener called GF-20 commercial outfits use to soften and press veneer. It's a glycol ether and not a sugar alcohol like glycerine. It's popular because it allows the veneers to quickly dry back down to moisture contents suitable for gluing.

http://www.veneersystems.com/images/products/H11-thumb-200.gif

http://www.veneersystems.com/

I'd call them and ask what glues it is compatible with, and I'd pose the glue compatibility question on woodweb for additional verification from those who use it regularly.

http://www.woodweb.com

I was faced with this very problem yesterday and today, gluing Brazilian 'marfim' (white wood) veneer to ply substrates in the main cabin, with contact cement (yellow stuff with the heavy vapour).'Marfim' veneer is notorious for getting wavy and crumpled, though it does look really nice once you´ve given it a coat of 2-part poly.

With a great deal of patience, plus some spit and polish, I managed to get by, not before sacrificing some veneer sheets in a couple of botchups, with all the attendant hassle of cleaning up the mess before initiating the next round.

That softening liquid could make life less hectic for a lot of 'marfim' veneer users.

[carioca1232001]

...............................Do a search here in B&R on using ethylene glycol as a rot preventative and ask those builders if they are gluing their treated wood successfully................



I consider myself a novice in matter of wooden-boat repair.

However, I´ve experienced wonderous results applying ethylene glycol+ boric acid + borax to rehabilitate infected woods (Dave Carnell´s recipe).

I have also epoxy-glued such rehabilitated woods some months after applying the aforesaid remedy, and have not noted any adverse results to date.

[Pericles]

As the natural wood veneer that prompted the thread seems to present such difficulties even before the challenges of bonding directly to the transom, why not bond the veneer to kraft paper first, to strengthen it. After all, the entire structure will need to be encapsulated with cloth and epoxy, so water penetration of the kraft paper should not be an issue. Some cabinet makers use a smoothing iron to activate heat activated adhesives when placing veneers.

http://www.basicadhesives.com/heatact.htm

It may seem anathema to some that I take this opportunity to mention high pressure laminates in a wood boat forum, but working surfaces in the galley can be granite or marble or stainless steel and the shower base and head are likely to be plastic.

Formica sent me sample of some of their latest designs. The brushed stainless steel is very deceptive, as is the Choco figured mahogany.F6933 Choco Figured Mahogany http://www.formica.co.uk/publish/site/eu/uk/en/home/collection/woodgrains.html

Before I am mocked, do take a risk and request your own samples. Never say never. There are horses for courses.

Pericles

[carioca1232001]

Ok, suppose you have managed to glue wood veneer successfully over ply with yellow contact glue.

Can anyone venture a guess if the glued veneer will accept a covering coat of 2-part laminating-epoxy, so as to seal it from the elements ?

In the past, I have brushed on 2-part clear poly over 'veneer glued over ply with yellow contact glue', without any problem at all.

This time, I would like to 'epoxy' first and 'poly' in succession.

[JimJ]

I vacuum bagged silky oak veneer to the transom of Sea Lark using slightly thickened epoxy.

I cut the veneer, peelply and wadding slightly oversize. I also cut the plastic that was to form the seal around the sides of the hull.

Then I did a dry run with the veneer stapled in place to make sure it all fitted.

Applied a layer of un-thined epoxy to both the transom and the veneer and allowed to soak in. While still wet, I applied a slightly thicken epoxy to the transom, fitted the veneer and held it in place with staples. The peelply and wadding were held in place with packing tape. I then sealed the sheet of plastic over the transom and sealed it around the sides of the hull. I applied about 5 psi of vacuum until the epoxy set.

I had to seal all the holes in the transom (outboard mounting, rudder fittings etc.) with packing tape on the inside of the transom.

Here is the result.

Jim


http://www.imagestation.com/picture/sraid222/pcf018c3912c7f0c491b229d453f1e4bd/eb23d0b3.jpg

[carioca1232001]

First, many thanks for your response.

Second, could you please answer the following questions:


1. What thickness is your veneer ? How wide are the veneer strips ?

2. What is 'peelply' ?

3. Ditto 'wadding' ?

4. 'Plastic' around the transom periphery ? Is it that blue strip visible in the picture you posted ?

5. Can you foresee problems putting a coat of sealing/laminating 2-part epoxy over 1,5 mm thickness veneer that has been glued over ply with yellow contact cement ?

Thanks

[Bob Smalser]

Ok, suppose you have managed to glue wood veneer successfully over ply with yellow contact glue.

Can anyone venture a guess if the glued veneer will accept a covering coat of 2-part laminating-epoxy, so as to seal it from the elements ?

In the past, I have brushed on 2-part clear poly over 'veneer glued over ply with yellow contact glue', without any problem at all.

This time, I would like to 'epoxy' first and 'poly' in succession.

Yellow Contact Glue?

I'm familiar with amber-colored, solvent-based contact cement and water-based contact cement that looks similar but looks like it has white pigment in it. When cured both are rubbery, and the veneer can even slip when exposed to heat. That's why UF resin formulations are used in most furniture instead of contact cement.

Yellow glue as I know it is a water-based aliphatic like Titebond. But there is a newer, related aliphatic veneering glue used by furniture manufacturers I've only read about and am not familiar with.

None of these are compatible with epoxy, but unless they have bled through the surface of your veneer, they don't have to be. Thin Titebond gluelines are successfully epoxied and glassed in stripper canoes because the epoxy bridges the thin gluelines. Any problems with epoxy not sticking to Titebond will come later if the hull is holed and a patch feathered in, as no other glues stick to Titebond, even more Titebond.

[carioca1232001]

The glue I used for veneer-to-ply is the solvent-based amber-coloured contact cement. It gets rubbery on drying.

My apologies for the loose nomenclature !

I actually bought a water-based white-pigmented glue and used it for a trial run, but it did not fare as well as the former, despite not exuding any noxious solvent-vapour when it was spread out.

No signs of the solvent-based amber-coloured contact cement coming through the veneer, so I shall put a coat of epoxy over the latter tomorrow morning.

It has accepted 2-part polyurethane in the past.

Many thanks. I don´t want to be erring specially now as this project is nearing termination.

[JimJ]

Carioca

1. What thickness is your veneer ? How wide are the veneer strips ?

The veneer was about 1.5 mm and a\bout 400mm wide


2. What is 'peelply' ?

Peelply is a nylon or dacron material used to allow the epoxy to flow into the wadding and then allow the peelply and wadding to be pulled off the veneer like a bandaid.
http://www.aircraftspruce.com/catalog/cmpages/peelply.php


3. Ditto 'wadding' ?

Wadding is a polyester wadding material that allows the vacuum to be easily distrubited over the whole surface


4. 'Plastic' around the transom periphery ? Is it that blue strip visible in the picture you posted ?

The blue is masking tape used while I painted the hull

5. Can you foresee problems putting a coat of sealing/laminating 2-part epoxy over 1,5 mm thickness veneer that has been glued over ply with yellow contact cement ?

Cannot offer any advice on that

Have a look at this site
http://composite.about.com/od/aboutcompositesplastics/l/aa000109.htm

Do a google on "vacuum bagging"

Jim

[carioca1232001]

JimJ,
Yours is a sophisticated veneer-over-transom epoxy lamination - and for a good reason. Mine is on the boat´s insides, a less demanding finish application.

I had a look at the site you supplied and have bookmarked it.

Many thanks again.

[carioca1232001]

..............

None of these are compatible with epoxy, but unless they have bled through the surface of your veneer, they don't have to be..... ..........


I´ve just got back from 2-part epoxying the veneer-glued-on-ply.

It worked fine and looks super !

Now for putting a couple of coats of 2-part clear poly over the epoxy... and I´m done !