will pl work for transom

[proshine43]

hello. I plan on putting in my transom this weekend and i want to see if pl is what i need. I plan on glueing 2 pieces of 3/4" exterior grade plywood together using pl, then glueing to the skin with pl. Is that correct. thanks for your help


Brian

 

[registeroot]

Re: will pl work for transom

hey, im planning the same this week sometime.

i think thats the way to go, but screw the two pieces together to ensure a tight bond.

then fibreglass the transom completely.

im unsure of what to stick it to the glass transom with, either resin or pl?

 

[Bob_VT]

Re: will pl work for transom

Well....... gorilla glue, epoxy or polyester resin are usually used ...... since the wood needs to be completely sealed with a resin (epoxy or polyester) you should have that "on-hand".

If you use polyester (fiberglass) resin you should include a layer of CSM (chopped strand mat) between the sheets.

Yes attach the sheets together and clamp for at least 24 hrs..... then "dry fit" the transom..... leave a bit of clearance since the next step is to completely seal up ALL sides and edges of the wood and let it dry. The drying time consumes the time and there are no shortcuts here.

Once everything is dry ....you can bed the wood to the transom with a layer of PL and clamp.... you guessed it....waiting time again.

If you are dealing with a fiberglass hull then you can tab everything together.

 

[drewpster]

Re: will pl work for transom

Both methods are used here. Depends on who you ask, but both will work. I prefer to use polyester resin and mat because I believe it leaves less voids than PL alone. (depends on how well you get it clamped)
I recommend that if you use PL, make sure you spread it evenly with a notched trowel. A simple S-bead is not enough in my book. It may bond together but it may also leave voids. In my view resin and mat are better because you get an even coat of your "glue" over the complete surface. As long as you roll all of the bubbles out of the mat before you put it together, and clamp it well with weight or screws, voids will be minimized.
(make sure you pre-wet the bare wood with resin and let it tack before you assemble)

I also recommend, regardless of how you glue it in, dont go crazy tight with the clamps. Just tight enough for good ooze out of goop. If you go too tight you can distort the surface and your engine mount wont sit flat. You need to keep the outside surface as true and flat as you can.

 

[Haffiman]

Re: will pl work for transom

When changing out old BMW and OMC drives to Cobra/VP/Merc, I normally used Marine Plywood, 3 layers of 450gr/mm between and screwed them together.
Never had any cracking or problems. Went a little 'low' on the catalyst, to give the resin time to properly soak into the plywood before curing.

 

[Woodonglass]

Re: will pl work for transom

Let's think about this guys. We are always talking about marine grade versus exterior grade ply and the difference is that ext. grade has voids and that we want the glue to be water proof. Ok, so when we laminate two pieces together we want to try an accomplish the same thing. We cannot do this usin PL. We can with Gorilla glue or any other type of waterproof wood glue Titebond III is and excellent waterproof glue for gluing plywood laminate. Provides maximum work time and allows you to ensure total voidless coverage. Clamps and screws will give you a totally permanent bond. I would seal the transom with a couple of coats with resin and 1.5 oz mat and pay close attention to the edges. For applying the wood to the transom skin I would Highly recommend using Peanut Butter resin. Use Cabosil, Resin, and a little less hardener than recommended to give you a little more working time, mix to the consistency of mayonaise and voila' you have a paste that will yield a voidless installation. Do NOT squeeze so hard that you squeeze it all out. Make sure you get a good even spread on BOTH surfaces and fillet the edes to give you a nice rounded corner for applying the glass later.

This is ONE way to do some clamping.

Post some pics so we can see what yer doin!
I'm just sayin...

 

[proshine43]

Re: will pl work for transom

Thanks guys for all your help. I'm on my way to lowes to pick up some titebond III like woodonglass suggested. Ill dry fit the pieces and I will be wraping it with 1708 then I will use epoxy resin with cabosil to adhere to transom. Now all I gotta do is find out what cabosil is. I'll be going to west marine in about an hour, will they have it? Thasnks again

 

[drewpster]

Re: will pl work for transom

It is also called aerosil and called colliodial silica. Yes they will know what it is if the right salesman is there. It will be with the cloth and resin if they have it.

 

[Woodonglass]

Re: will pl work for transom

They might but if NOT check with your local body shops that deal with fiberglass repairs. They will be able to tell you where to get it. It is a Thickening agent that you add to the epoxy resin. Add just enough to make it like Mayonaise.

I'm just sayin...

 

[bcddd214]

Re: will pl work for transom

The easiest and strongest way is also the most costly but is does a FLIPP'N amazing job and will reduce the weight of the boat a buttload.

Use honeycomb core which is easy to work with and if you ever get a penetration, the leak won't expand NEARLY what wood will do (it won't sponge) and will lighten up your transom a buttload.

First 2 layers do with carbon fiber and finish off with 8 layers regular mat and woven or your favorite fiberglass flavor.

Light weight, strong as hell and more resilient to damages.

The money you save in time will FAR outweigh the additional cost. Quality chemical distributors will gladly 'tech support' you as well when you are working with these advanced products.

 

[ondarvr]

Re: will pl work for transom

First 2 layers do with carbon fiber and finish off with 8 layers regular mat and woven or your favorite fiberglass flavor.

Please explain this combination of products.

 

[bcddd214]

Re: will pl work for transom

all carbon fiber is, is really bad *** fiberglass that is a royal pain in the butt to cut. You have to use really classy sewing/leather shears to even stand a chance against it.
When coated with resin (just like fiberglass) it increases flex and is pretty impossible to shatter unlike glass. I have seen it tear but when you look at the magnitude it took to split it, you can see why they use it on the space shuttle.

The only difference between carbon fiber you buy at the store and the carbon fiber NASA uses is the resin. NASA doesn't use it. They heat the carbon fiber to I think 1800 degrees and melt it together. Something like 36,000 lbs of force per sq inch to break the stuff when done without resin and feather weight.
But it's the SAME stuff!

 

[ondarvr]

Re: will pl work for transom

You have a bizarre concept of how these products work (or don't work) together.

 

[Mark42]

Re: will pl work for transom

The best and easiest thickener I have used for both epoxy and polyester resins is EZ Thick. Its cheap, a little does a lot, and makes a very strong thickened resin. Outstanding product. Its white, and resin can be thickened to the consistency of mashed potatoes easily so it can be troweled on or even sculpted if you want. Stuff just won't run or sag, even when the heat of curing warms it up.

http://www.epoxyproducts.com/2_fillers.html

 

[bcddd214]

Re: will pl work for transom

nope, an associates degree in polymer science and about 15 yrs hard core hands on experience.
I can't possibly imagine what you are indicating carbon fiber is used for or 'as'...

You have a bizarre concept of how these products work (or don't work) together.

 

[bcddd214]

Re: will pl work for transom

Cabosil and resin is a winner too!

The best and easiest thickener I have used for both epoxy and polyester resins is EZ Thick. Its cheap, a little does a lot, and makes a very strong thickened resin. Outstanding product. Its white, and resin can be thickened to the consistency of mashed potatoes easily so it can be troweled on or even sculpted if you want. Stuff just won't run or sag, even when the heat of curing warms it up.

http://www.epoxyproducts.com/2_fillers.html

 

[ondarvr]

Re: will pl work for transom

Two layers of carbon and then 8 layers of mat would be a terrible laminate schedule for either polyester or epoxy, this combination of produts don't combine to create the best, or even close to the best laminate for anything, let alone a transom.

 

[bcddd214]

Re: will pl work for transom

Doesn't make a difference if you are working with a chemical bond.
a mechanical works fine to as long as it is clean...

Two layers of carbon and then 8 layers of mat would be a terrible laminate schedule for either polyester or epoxy, this combination of produts don't combine to create the best, or even close to the best laminate for anything, let alone a transom.

 

[ondarvr]

Re: will pl work for transom

When coated with resin (just like fiberglass) it increases flex and is pretty impossible to shatter unlike glass. I have seen it tear but when you look at the magnitude it took to split it, you can see why they use it on the space shuttle.

Carbon laminates, unlike glass fiber laminates, can be very brittle, they don't flex much and when they fail it tends to be a catastrophic failure. This is further compromised if used with polyester resin.

 

[bcddd214]

Re: will pl work for transom

If you are not trying to mix polyester with vinylester, you are oky doky!
Thats like trying to stick a plastic coke bottle to butter. Doesn't work.

Doesn't make a difference if you are working with a chemical bond.
a mechanical works fine to as long as it is clean...