Best time and method to expoy glass in?

[bhackford]

I need to epoxy in fiberglass on a skiff I am building. It is best to start in the evening with falling temps or the morning with rising temps?

I was going to lay fiberglass out then wet out by pouring and rolling. All tips are appreciated.

Thanks

[JimD]

I like to start mid to late morning on a warm to hot sunny day. Leave the wood in the morning sunlight so it gets good and warm. Then glass. You should be able to get a couple additional fill coats on by evening, three applications in all. With a little luck the weave will be filled and no more epoxying required. I don't like rollers. Much prefer soft plastic spreaders. They spread the epoxy very quickly and evenly. These Bondo brand spreaders are as good as any and are available everywhere
http://ecx.images-amazon.com/images/I/21V-T3JTD2L._SL160_AA160_.jpg

[bhackford]

Thanks for the feed back. Do you know of a epoxy calculator to ensure I have enough epoxy before I start? Thanks

[JimD]

What weight cloth are you using?

[JimConlin]

If you plan on a clear finish, don't glass the boat when the temperature is rising. Otherwise, don't worry.

Pour and roll is OK, but I prefer plastic spreaders. Covering the gooped glass with peel-ply will give you a filled surface in one application.

150% of the weight of your glass is enough..

[the_gr8t_waldo]

rather than rolling out the epoxy, i've had great results useing auto body puddy spreaders. the dril is to pour out the measured and mixed epoxy onto the flat surface and with the spreader you move it along and into new areas that you want to wet out. ( yeah vertical areas require that you move a lot faster, but once you get the hang it it, you'll be able to manaige) there's lot less waste useing this. once the plywood is wetted out you unroll the fiberglass onto the project and pour some more epoxie and push back n forth over the area your working on and once the fiberglass turns clear. you push the excess epoxie into the next area you want to work. plywood dosen't absorb epoxie too deeply, but you want max. penatration there(to help this stage of the project i like to thin it out a little. use some acetone-10% or less- this is just for the first wetting out of the wood.). with that in mind i'd start in the evening when temps are cool and keep pouring epoxie untill either no more is being absorbed, or what is in there starts to fire off. then roll out the fiberglass onto the hull. you'll want to do all of this in a protected area and see to it that dew or high moisture isn't present during the hardening process. once it starts to harden and there's no danger of the epoxie draining out from the cloth( leaving air bubbles in the cloth) you can relax. when the temps start to climb the next day everything epoxied will fully harden . mix small batches (i'm thinking that in my own shop i mix up about 8oz at a time) and use it all b4 mixing some more stuff.peilply is some great stuff it might be worth, it if you look it up and find out if it's worth it to use on your project

[D Happ]

When I use plastic spreaders, it seems to push a lot of very small air bubbles into the epoxy. It can become frothy if I work it too much. Does this happend to you guys also, and what do you do about it? What am I doing wrong?

[Canoez]

D Happ - I think you hit the nail on the head - you're working the epoxy too hard and basically whipping air into the mix with the spreader. You will want to go back over the first coat with the squeegee to remove excess epoxy if you are building a lightweight or bright finished boat.

One good trick with the yellow poly squeegees is to drill a row of widely spaced 1/2" holes near the top - it gives you something to hang onto when things get a bit slippery.

[RodB]

Pouring and rolling will work, but a squeege (yellow plastic spreader) is much better if on a horizontal surface... (for the first two coats). Angled and vertical surfaces require a roller in conjunction with a squeege.

Lay the cloth down dry, tape if necessary on the edges. You mix the epoxy... and pour around in a "S" shape... and begin to squeege... pushing the epoxy into the cloth, continuously expanding until the epoxy runs out... mix some more and continue on.

The squeege allows you to easily achieve the amount of epoxy desired in the cloth wetout, without leaving any pools. The techinique is quite intuitive, and you will figure it out pdq.

I have not seen much "gassing" when glassing unless the temp change is quite a bit after you have applied epoxy... with a reasonable temp range you should be fine. What is your temperatue range throughout the day? I prefer glassing in warmer temps, like 75-90 degrees. In cooler temps, the epoxy is thicker and flows slower (levels itself slower). A typical spring day here is a 60 degree low, with a high of 80.... In this condition, I would begin late morning and not even pay attention to the temp... if it were colder in the morning, I would probably wait till late morning (as above) then begin, with the goal of appying the final coat that day. Normally, I would want to complete a glassing job with all coats applied that day, even if I was still at it at 9PM... You want that chemical bond...as if all were applied at the same time.

Gassing should only a problem with the first coat, so that is when you want a reasonable temp range that will not make for air expansion in the wood to become a problem. As mentioned above, you could place the ply in the sun to warm it.... then bring it inside and glass it... thus it is cooling and should not vent air. Remember, wood is slow to heat so this is not a 5 minute deal. If you have a fairly consistent temp range while you are applying the first wet out coat, you are not likely to have problems. You just want a temp equilibrium between the ambient temp and the interior of the plywood.

With fast or medium hardener, you should be able to do all the required coats in one long session, applying successive coats approx an hour or so apart. I always try to use fast hardener if I can, it just makes the whole job go much faster. In my hot climate, I can use medium hardener and have epoxy tack free in an hour, but unless I am glassing in 90 degrees plus, I usually use fast hardener.

After the initial wetout coat... then the second coat is another squeege coat that goes very fast as you lightly run the squeege across the top of the cloth, filling the weave a bit more. The final two coats are rolled and tipped with a foam brush. You want to cover the weave enough to allow for sanding to a nice satin finish (80grit ROS). You can combine the final two coats into one coat if you pour it on thick and can maintain a uniform coat with rolling and tipping. I have adopted a standard technique of 4 coats on larger jobs for very consistent results. The rolling is done with a 3" roller (cutting the standard 7" roller pads in half) and covering about 10 square inches with each loading, then immediately tipping with a 3" foam brush. This allows for amazingly consistent results and an very smooth level surface... which makes for less sanding. FYI, a small platform (platten) is used to pick up the epoxy (12" by 12") (instead of a roller pan). This allows you to mix about 3 ounces of epoxy at a time and to avoid waste by using a squeege to scrape every last drop onto your roller pad.

Hope this is not too much info...

RodB

[Charles Burgess]

In order to get the best bond between layers, you need to get it all done within 16 hours from beginning to end.

[Candyfloss]

Lordy, Lordy, we do it very different here in New Zealand!
First, your surface preparation must be impeccable. All holes, including the tiniest, must be filled with glue. All exposed end grain must be filled, otherwise air bubbles will form under your cloth. I take it you are using 260g boat cloth; that is, woven cloth, not csm or bi-ax? Cut your cloth to approximately the right shape & roll it up over a cardboard core. Have a cup of coffee & visit the bathroom whether you think you need to or not. Don overalls & gloves. Smear glue over any hard corners. Then roll a coat of epoxy over as much as you can handle in one hit, or the width of your cloth plus a bit, being careful not to lift the glue off the surface. I prefer to use a foam roller cut in half; you can buy half-width roller frames. Then roll out your cloth starting from the top; gravity is your friend & you need all the friends you can get. Try to keep the grain of your cloth square & straight, at least in the middle of the cloth. It will probably converge towards the ends. You can carefully tug on the edges here & there to achieve this. Be careful not to shred the cut edges. Roll a coat of epoxy over the top of your lay-up, then roll the whole lot out with a 100mm wide ridged metal roller. I don't know how else to describe this thing; it looks like a 10mm bolt thread, drilled thru the center & hung on a frame. I believe they make them for the panelbeating industry. We got ours from the auto paint wholesalers. Start from the center of the cloth & work outwards making sure to chase any air bubbles out. Wet out the next area of boat, overlap your cloth about 50mm & proceed. Go back & check for air bubbles. If there are any try rolling them out again. If it comes back you have missed a hole. In desperation make a tiny cut in the cloth with a sharp craft knife in the middle of the bubble. When it has all tacked off, make a very thin mix of epoxy & microbaloons & roll it over the top. This will make sanding much easier. Who cares what time of day it is? Work in manageable chunks & all will go well. The only times I ever got into trouble is when I bit off more than I could chew. When you have finished put a small heater under your boat, clean up & break out a beer. If you are still awake, it is easiest to trim the ragged edges off with a craft knife before the resin sets off completely. Too soon & you might dislodge the glass. Too late & it will be too hard. You can grind it off afterwards, but it is messy & itchy. The edges are sharp & dangerous. Be careful.