Glassing floor in 23 body

[ruggs]

Why not just use polyester resin, cheaper and ,after all ,that's what the body's made of ?

dave

Dave,
JMO... There isn't anything wrong about using polyester resin, in fact your probably better off to keep with the original material when done properly. Sometimes what people read on the web screws things up. When you do it for a living you really get a better perspective of right and wrong. I'm going to PM BC from Spirit and see if he will put in his pro 2 cents worth into this thread........ruggs

 

[RocknT]

That would be good ruggs thanks ..

 

[Wild Mango]

Why not just use polyester resin, cheaper and ,after all ,that's what the body's made of ?

dave

Because epoxy sticks to wood super good and to polyester pretty good. Whereas polyester doesn't stick to wood worth a damn no matter how you prepare things.

 

[ruggs]

Because epoxy sticks to wood super good and to polyester pretty good. Whereas polyester doesn't stick to wood worth a damn no matter how you prepare things.

Mango,
With all due respect I disagree, the type of plywood that you choose is the factor, use marine grade and polyester resin works just fine. If you choose to go cheap is where the problems start. Prep of the plywood is also a major factor. No disrespect, just what I know to be true.......ruggs

 

[2old2fast]

I do know this, I embedded both wood and steel imbedment plates into the body close to 15 years ago with polyester based filler [like "kitty hair"] . due to some changes, I had to remove 1 of each 2 years ago. The only way to get them off the surface was w/ an air chisel and grinder, I'm no chemist or structual engineer, but they seemed to be pretty damn secure . The imbedment that holds my gas pedal was insalled the same way , and god knows that gets abused . Just sayin'


dave

 

[lamin8r]

I havent been on here in a very long time,,but,heres my input..
I only use polyester to lay up my product,,and when I glass over ply,,I use a locally based preparation,AFTER I have sanded the surface of the ply well,,or given it a good roughen up with a grinder,with 24 grit disc..Dont have to go hog wild..I then brush a good coat of polyester resin onto the plywood,,and,the next day,when its dry,,give it a good roughen up again..If you dont have any dry patches,,glass the floor to the body using the above methods.,,just make sure the body has been scratched up well before you do it..I dont believe in mixing materials,,its a bloody disaster,,if its poly,repair with poly..I have to deal with makeshift repairs every day,that other people have done before me,,with these stinkin little repair kits from the local auto store..Invariably,the whole lot gets ripped off,so I can key it altogether again with polyester..I havent had any problems yet,,apart from the motor racing guys undoing my work against one of their competitors cars...

 

[woosterken]

talking about rolling out the glass , on a boat forum iam on ,this handy dandy tool was made..

http://forums.iboats.com/showthread.php?t=263185&highlight=DIY+FIberglass+Roller

hope it helps
woosterken

 

[Wild Mango]

Mango,
With all due respect I disagree, the type of plywood that you choose is the factor, use marine grade and polyester resin works just fine. If you choose to go cheap is where the problems start. Prep of the plywood is also a major factor. No disrespect, just what I know to be true.......ruggs

Ruggs, happy to be disagreed with by a brother. It could be the grade of polyester we commonly use here is different, but we have learned through bitter experience not to try to bond wood. As lamin8tr says, a surface prep (we use epoxy) and a scuff works OK. Of course we would never mix resins in a layup even for a repair. All our ply for survey is BS 1088, unsure what that equates to in your ABS standards, but correct about the cheap stuff as a road to disaster........

 

[donsrods]

The epoxy vs polyester resin has been argued so many times and there is never a clear cut winner. Some people love one and some love the other. Personally, I retired from the boat industry and have built and rebuilt a lot of boats in my lifetime, as well as a few fiberglass cars, and have used both. Epoxy does have a couple of advantages, but the cost factor kinda outweighs them IMO. I use polyester when doing any fiberglassing work and the interior in my 27 was done that way 23 years ago and is still like the day I did it.

There are two kinds of polyester resin. One is called laminating resin and it is used primarily where you will be laying up successive layers of mat or cloth. It has no wax in it to promote curing, so the top layer will stay sticky unless you put a coating over it to inhibit air from getting to it. The other kind of polyester is finishing resin and it does have wax, and as long as you keep putting successive layers on before it cures you do not have to worry about the wax. But if you wait until it kicks you need to remove the top layer of wax or the next layer will not adhere well.

Almost every boat and most fiberglass bodies are made from polyester so any additions or repairs you make can be done successfully with polyester again. If you don't mind spending the extra money, go with epoxy, but I buy my polyester resin out of a 55 gallon drum at a marine supply house and put the money saved into stuff to make my car go faster.

Don

 

[409T]

There are two kinds of polyester resin. One is called laminating resin and it is used primarily where you will be laying up successive layers of mat or cloth. It has no wax in it to promote curing, so the top layer will stay sticky unless you put a coating over it to inhibit air from getting to it. The other kind of polyester is finishing resin and it does have wax, and as long as you keep putting successive layers on before it cures you do not have to worry about the wax. But if you wait until it kicks you need to remove the top layer of wax or the next layer will not adhere well. Don

Does that mean that you should not paint over laminating resin? If so and you should only paint over finishing resin, I'm going to guess that you would have to remove the wax first. Is that right? If so what do you use to get the wax off?

Jeff

 

[donsrods]

You couldn't paint over laminating resin unless you sprayed something over it first to make it cure. It will stay sticky until the air is kept away from it. They sell a product for that purpose. As for finishing resin, yes, you have to remove the wax first. What you want to do is wipe it down with acetone, changing rags a lot, to remove most of it. Then sand it completely to a dull finish, then wipe it down again very well with acetone. If you sand before you wipe it down the first time the wax goes into the sandpaper scratches and will come back to haunt you.

Here is a pretty good article I found on line about resins:

http://www.pyacht.com/evercoat-laminating-resin.htm

Don

 

[madmike8]

I have a reaction to polyester, so my choice is made for me on what I use. My question is how much should I purchase if I'm going to lengthen my body and do the wooding and floor? I'd rather have extra than not enough.

 

[donsrods]

Hard to say, but probably more than you think. One way to go would be to buy your epoxy in gallon cans and return the unopened ones you don't use. I have worked with the West System epoxies and what is nice about their line is that they have "ratio pumps" that pump a specific amount every time you push the plunger, so you don't have to do any math in your head. So if it is a 3 to 1 ratio, the pump for the hardener pumps out a third the volume of the one for the resin. All you have to do is push the plunger on the resin a certain number of times then push the one on the hardener the same number of times and you will get the exact ratio you need for a proper mix. The system is not cheap, but it really makes it easy and pretty mess free.

You are also going to use more of the other products like stir sticks, plastic tubs, and throwaway brushes than you can ever imagine. I buy those things at a auto paint store by the box when I am doing glass work and it always amazes me how many you use. Also get yourself a box of latex gloves as you will use a bunch of those too.

Don

 

[Wild Mango]

We use West System and the ratio pumps and it all works pretty fine. Make sure your mixing tubs have no corners for resin to hide in and escape hardener. Put the resin in the tub first, keep the volume low since epoxy will run away if its in a mass that holds the heat of reaction. You can keep mixing as you go along, provided the fresh batch incorporates all the last batch dregs. If you get resin on you, as you will, wipe or wash off with plain old vinegar, no where near as dermatitis evil on your skin as acetone. Top class boatyards use 1000 Island Dressing instead of vinegar, of course. (I wazzin kidding about the vinegar though) Happy Fabricating!!!!!

 

[ruggs]

Glad to see this thread come back to life, there is alot more to fiberglass fabrication than just the itch and scratch. Maybe while talking about this someone should mention the difference in strength between a 90 degree joint and a radiused 90 degree ........ruggs

 

[hemiguy]

Wow. I brain was on overload..these threads are so valuable to a new builder...thanx. You guys rock