All about resins (Cliff Notes added to top of page 1)

[Bronc Rider]

Re: All about resins

Re: All about resins

Well, I think it stands that most on the forums would rather over engineer for the sake of "knowing" the work will be good than to omit a step that others have taken and have had good result

If your area is clean of the old contaminants the acetone is fine to use if it makes you feel better about it. FRP is to pourus to simply wipe away contaminants. The layers must be removed completely until you hit clean glass. If there was delamination or holes that had some type of liquid intrusion sometimes entire parts of the hull will have to be removed and replaced if grinding doesn't reach clean glass. Its not worth it sometimes especially if it was due to impact. Then again some people enjoy resurrecting those old floating beauties.

 

[redfury]

Re: All about resins

Re: All about resins

Then again some people enjoy resurrecting those old floating beauties.

Well, you did join a forum with a bunch of crazies, what do you expect?

Now, I have a question for you...two actually.

If all that is necessary is to have a clean surface ( no contaminants ) how long can you let unwaxed resin sit before you need to "prep" it for another layer of glass...meaning, layed up an area with glass, and then come back to it later to do more work. Would washing it down with water be enough to get rid of any contaminants, or ???

What about unwaxed resin....does the last layer have to have wax, or would a layer of paint, etc do the same job as the wax. Will it be detrimental to just leave it be....the waxed/unwaxed resin properties and how the unwaxed reacts to "x" is still a pretty big unknown to me.

 

[Trapper55]

Re: All about resins

Re: All about resins

I am still working on my 14' TomBoy fishing boat on the weekends so a week goes by without touching the resin applies to the wood. I always sand, vacuum and wipe it down with acetone before I apply resin and cloth. I don't know if I have to do this or not but compared to grinding it's not hard and I feel more comfortable about my resin job when I do it this way. I am using US Composites non-wax resin and I have had no problems so far. I have also order CSM, cloth and an aluminum roller from them. I bought 5 gallons from them and so far I have used 2 1/2 gallons on the transom with 1 coat of resin on the deck pieces and stringers. I will probably have to purchase more resin because the CSM seems to really soak it up. I think I read somewhere on this forum that the non-wax resin won't cure completely unless there is no exposure to air. That means to me you would have to use a wax version as your finish coat or paint it. I'm sure 1 of the other posters on here knows for sure. Don't forget that you will have to pay a hazardous shipping fee when you order from US Composites. I think it is about $50.

 

[HVAC Cruiser]

Re: All about resins

Re: All about resins

Im new at this but from what I have seen, non-waxed stays tacky you have to add wax for the final coat. I have been doing the same as Trapper. One thing I have found to make quick prep sanding work of the hull and bulkheads I am working on is using my belt sander, I have it hooked to my shop vac so it also reduces the amount dust.
I also found the belt sander works great where I am replacing the stringers , it gives me a nice even mating surface

Bill

 

[system-f]

Re: All about resins

Re: All about resins

Another question, what is the deal with waxed and unwaxed resins?

 

[bigbad 4cyl x2]

Re: All about resins

Re: All about resins

i use acetone before i grind and after ,im overweight and climbing around the inside of the boat with out a floor was hard, i used epoxy because it is forgiving for the novice , buy it in 5 gallon jug kits .dont bother with the gallon kits and you'll turn out ok

 

[redfury]

Re: All about resins

Re: All about resins

Another question, what is the deal with waxed and unwaxed resins?

What I can tell you about the two is that unwaxed resin is what you use when you are building up layers of fiberglass...either all at once, or in succession. Waxed resin is for finishing work, meaning you have no plans to add more fiberglass to the project. When the waxed resin goes through its curing cycle, the wax rises to the surface creating an oxygen deprived environment which allows the resin to harden. If you have to add more fiberglass later, you need to dewax the fiberglass before adding more to it, and this applies to the fiberglass if its an hour old, or 30 years old.

 

[ondarvr]

Re: All about resins

Re: All about resins

Another question, what is the deal with waxed and unwaxed resins?

Forget about waxed resin, there is very little need for it in any application, it only creates more work.

 

[chrishayes]

Re: All about resins

Re: All about resins

Bronc, no hard feelings. I too was being sincere when I said that we as noobs appreciate an expert or professionals opinions and tips. Afterall, if all us COULD produce pro results we WOULD. Thanks for your comments. By all means continue to educate and help us all to understand. I believe and preach grinding as well to be the be all end all way to prep. However, I cant say that I have ever done ANY work on my boat where I didnt sweat enough for it to drip, sometimes poor, from my face and arms onto the surface im about to glass. Not to mention the oils in your skin that most likely have touched the surface, not to mention whats on my shoes. Would this not be the right place for a solvent cleaning?

Ondarvr, I am curious as to whether you feel acetone is necassary? I dont mean a replacement for good prep, but as a final surface treatment before layup on a well prepped(grinded) surface.

All I can say is that I have used both damp cloths and acetone to remove any dust or other particles that may or may not have collected on the area. Afterall it is usually a horizontal surface in a garage so there is not only the glass dust to worry about but also the regular livin in the country dust and debris that may be floating around and settling. When I use a damp water soaked rag, the surface does not appear to be as clean as when using acetone. THe surface looks virgin once acetone hits it and evaporates. There is no scientific basis to that but the sight factor is there. Does it matter?

 

[drewpster]

Re: All about resins

Re: All about resins

Here is the deal as I understand it. ondarvr is more experienced so chime in if I am wrong.
Just as redfury wrote, polyester resin is air inhibited meaning the surface layer of resin will remain tacky until it is deprived of oxygen. This is a good thing because it allows you to add additional layers of fiberglass on to a partially cured layer. This provides a chemical bond between the hardened layer and the wet one. The only time you need to use wax (or other sanding aid products) is in a final layer you intend to sand smooth for finishing. This includes gelcoat. Gelcoat will also remain tacky if not deprived of oxygen.
On hardened (not fully cured) layers that feel tacky to the touch you can go ahead and add layers without acetone. In fact, if you wipe down the tacky layer you risk removing it which defeats the purpose.
If you are covering glass that has cured for several days it is best to wipe it down with acetone. When you do you should feel the tackiness come back. Then go ahead and cover it.
If it has been allowed to cure for too long it may be more difficult to get the tack back. So you may have to do some light sanding to insure good adhesion between layers.
If you sand and the paper chokes up and generally wont work then the glass is fine to cover after a wipe down with acetone.
It is always best practice to lay up all your layers all at once depending on the thickness of glass you want to achieve. In very thick areas it is best to use less catalyst to prevent the lay up from over heating and cooking the resin. I have done a complete lay up (2CSM 1roving 1csm 1roving 1csm) in one session. It developed very moderate heat. I used about 60% of the catalyst I normally would. And the work was done at room temp. (about 75 deg.)
It is not always practical to do a complete lay up in a given session. I have been about a week at a time between subsequent layers. I have always had good luck using acetone to get the tack back.
Under the deck it is not necessary to use wax since you are not working on a finished (paint or gelcoat) surface. I did use wax in the final layer just to provide a hard cure. You only need to use wax in a final layer you intend to sand smooth. If you need to add layers to glass that has been waxed all you need to do is a little sanding and an acetone wipe down to remove the wax. Then you can lay more glass down.
make any sense?

drewp

 

[Bronc Rider]

Re: All about resins

Re: All about resins

Well, you did join a forum with a bunch of crazies, what do you expect?

Now, I have a question for you...two actually.

If all that is necessary is to have a clean surface ( no contaminants ) how long can you let unwaxed resin sit before you need to "prep" it for another layer of glass...meaning, layed up an area with glass, and then come back to it later to do more work. Would washing it down with water be enough to get rid of any contaminants, or ???

What about unwaxed resin....does the last layer have to have wax, or would a layer of paint, etc do the same job as the wax. Will it be detrimental to just leave it be....the waxed/unwaxed resin properties and how the unwaxed reacts to "x" is still a pretty big unknown to me.

How long can it sit before you would have to re-prep? Sometimes my guys do all the grinding and dust removal in the morning and lay up in the afternoon. 16 hour days are not unheard of, all the prep is done in the morning. If we are inside a tank (no worries about rain), we sandblast and clean the first day and lay the rest of the week. Before glass is layed we put a fresh coat of resin, no acetone even four days later.
The only time I would use waxed resin would be for a top layer that was going to be left bare, no other top coat. The wax will keep it "fresh looking" for much longer. If a top coat is going to be used you could potentially be raising bonding issues if wax was used. Most pipes/tanks you see in chemical plants had a pigmented waxed top coat. No wax mixed in the resin used for lay up.

 

[ondarvr]

Re: All about resins

Re: All about resins

As normal practice in the industry, I would say far more don't do an acetone wipe.

If you've ever tried to remove something you "can" see from a surface with acetone, you know it frequently evaporates before the stuff is picked up by the rag. This leaves a thin film of whatever it is on the entire surface, not just the one spot. If you "can't" see the contaminate, then it would be difficult at best to makes sure it was removed and not just moved.
Its kind of like that wet rag they use at restaurants to clean tables with, the first table might be a little cleaner, but the last of the 5 tables cleaned just gets a mix left on it of everything that was on the 4 tables before it.

Other solvents work much better than acetone when prepping a surface for paint, where any contaminate will be more likely to show up immediately.

Most shops would discourage the idea of spreading such a flammable liquid around on large surfaces where a static spark could ignite it.

 

[Bronc Rider]

Re: All about resins

Re: All about resins

It is always best practice to lay up all your layers all at once depending on the thickness of glass you want to achieve. In very thick areas it is best to use less catalyst to prevent the lay up from over heating and cooking the resin. I have done a complete lay up (2CSM 1roving 1csm 1roving 1csm) in one session. It developed very moderate heat. I used about 60% of the catalyst I normally would. And the work was done at room temp. (about 75 deg.)

This is another instance where I would do things differently. Instead of buying promoted resin I would buy it "raw" (glass shops around here sell it that way). You can add DMA and Kobalt yourself. Regardless of the outside temp I will still add the standard 1oz of MEKP to 1 gal of resin. I can make the resin kick in 5 minutes or 45 minutes regardless of temperature and only use 1oz to 1 gal ratio. There are charts to show you how much to DMA and Kobalt to add based on your current temp, humidity etc. The catalyst should stay the same no matter what, the constant is the accelerators.

 

[chrishayes]

Re: All about resins

Re: All about resins

Thank you ondarvr. I wonder then why it is so widely accepted here to use it? I like your comments on the rag at the diner. That is why I always wipe with a clean side of the rag in one direction but if there is no reason for it then hell, guess a lot of us are wasting our time:redface:

 

[Bronc Rider]

Re: All about resins

Re: All about resins

One last comment.
The tack everybody likes to get with the acetone rub I would consider bad. I use resins that once cured (even 20 minutes later) would never get tacky again, not even if acetone was poured on it for weeks straight. This resin won?t break down with acetone. The fact that the resin gets tacky in yalls situation would make me think it was structurally compromised (just a little bit).

 

[redfury]

Re: All about resins

Re: All about resins

I hope everyone else is sucking up this as much as I am trying to

One question I've got for the fiberglass Guru...water and freshly laid glass, wash down situation, standing water....it's an issue for some of us that have to do this work outside in the elements. My problems were prep issues, but I wouldn't have really seen them if the water hadn't turned the glass white.

I'd love to hear your insight/experiences with water and fiberglassing.

 

[Bronc Rider]

Re: All about resins

Re: All about resins

One question I've got for the fiberglass Guru...water and freshly laid glass, wash down situation, standing water....it's an issue for some of us that have to do this work outside in the elements. My problems were prep issues, but I wouldn't have really seen them if the water hadn't turned the glass white.

I'd love to hear your insight/experiences with water and fiberglassing.

Not sure if I understand the question. Are you asking what we do to keep the area dry? If you are this is what we basically do.
We build plastic enclosures for our work area (we call it a hooch). To keep our sweat off the work area we do silly things. We put on sweat bands, tie rags on our wrists to keep sweat from dripping of our arms and keep rags handy to wipe our face. For our feet we use those rubber booties that fit over regular shoes. In a pinch plastic bags taped up will work. Sweat on the lay up area is an issue we always fight over here in the south. If a guy does sweat all over it, you can bet he is going to grind off every bit of the compromised glass (read no fun at all). And it does happen, you just can?t stop yourself from sweating (like I even had to point that out).

 

[Mark42]

Re: All about resins

Re: All about resins

I found that using a shop vac to clean out the dust before wiping with acetone makes a big difference. Got to get as much dust out of the crevices as possible. With Poly resin, its a good mechanical bond that will make it last. So clean scratch marks is what you want to glass over. No sanding greater than 80 grit should be glassed over IMO.

 

[ondarvr]

Re: All about resins

Re: All about resins

This is another instance where I would do things differently. Instead of buying promoted resin I would buy it "raw" (glass shops around here sell it that way). You can add DMA and Kobalt yourself. Regardless of the outside temp I will still add the standard 1oz of MEKP to 1 gal of resin. I can make the resin kick in 5 minutes or 45 minutes regardless of temperature and only use 1oz to 1 gal ratio. There are charts to show you how much to DMA and Kobalt to add based on your current temp, humidity etc. The catalyst should stay the same no matter what, the constant is the accelerators.

When you say glass shops, you must mean fiberglass distributors, most retail outlets don't sell unpromoted resin (which is typically VE), they may be able to special order it, but then the cost goes up. Plus there is the other issue of needing to buy DMA and cobalt, both of which can be very dangerous if handled or stored incorrectly. Frequently people don't get the correct amount of catayst added to the resin, so adding two more items in the exact amount may even create more problems.

 

[Bronc Rider]

Re: All about resins

Re: All about resins

When you say glass shops, you must mean fiberglass distributors, most retail outlets don't sell unpromoted resin (which is typically VE), they may be able to special order it, but then the cost goes up. Plus there is the other issue of needing to buy DMA and cobalt, both of which can be very dangerous if handled or stored incorrectly. Frequently people don't get the correct amount of catayst added to the resin, so adding two more items in the exact amount may even create more problems.

Yes, I do mean distributers. We have a few here open to the public.
As you point out, they can be dangerous. I take it you have seen someone add MEKP to Kobalt without mixing it in the resin first. For the part time restorer I do agree, best to leave out the extra chemicals. I have just seen it to many times where someone is trying to manipulate the "kick time" with catalyst alone. It can be done, but only to an extent.
BTW, I enjoy reading your post's, you have great knowledge when it comes to hull construction.