how to layup with vinylester correctly?

Hi,

I've got some coosa parts that are getting glassed into existing hull structure, stringers mostly and some small bulkheads, which I'd like to use VE for. I've got a 5 gallon bucket of a vipel VE, not sure which vipel formulation exactly but was told it was unwaxed and for hand laminating at the supplier, who is a good supplier but isn't a boat builder.

What I'm second guessing with the stuff is when you have any thickness at all of the resin, ie anything more than what you might swipe on with a paint brush, it maintains no tack whatsoever. A real thin layer that doesn't generate any heat seems to maintain some tack for awhile on the side exposed to air (like this morning I noticed my test from last night, peeled it off the plastic I put it on, top was tacky bottom was not).. For instance comparing it to polyester, with polyester I could tell the difference between waxed and unwaxed, it's obviously tacky when unwaxed after sitting for months even, where the VE with any thickness to it is 100% cured to the surface from what I can tell.

My usual laminating process with polyester, since I do it in between a day job, is I show up some night, say a Tuesday night, add a layer. Then I come back on another night in short proximity, say the following Thursday, and add another layer.. With 2 part epoxy I may time things so I can come back in the AM and get a 2nd layer prior to full cure but if it cures I clean & sand...

So my question is basically, with the VE, if I come back in 24 or 48 hours after I lay it up and it is tack free, do I need to sand? Or does it bond to itself just fine without sanding for some period of time? How do people normally work with this stuff, do they put all the layers on in the same day to achieve a chemical bond? What's different about the process versus polyester?

Thanks in advance!

Jon

 

The exact resin formula makes a big difference, most VE's tend to be slightly sluggish, so in a thin film they tend to be rubbery, but even in a thicker laminate the surface doesn't cure tack free quickly, so a day or three is normally Okay. If this is a skin resin (used for thinner laminates and designed to cure quicker), then it's possible for it to be tack free sooner. Also many skin resins are a blend of VE and DCPD, VE doesn't like to cure, DCPD cures easily and will cure tack free quickly, possibly creating bond issues. Is there a resin code on the pail, or can you get it?

Most resins are good for at least 24 to 48 hours with no surface prep, others for a week or more.

 

Thanks!

It didn't say on the jug but I just called and the supplier had that immediately, F010-TBN-23.

 

I'd definitely say - thin film, rubbery, thick film tack free, kinda 2 modes. In my application will be laying up 1708, what I should do and I will tonight, is saturate some 1708 to see what the effect is at that thickness too.

 

http://www.aoc-resins.com/images/uploads/F010 Series_us_1.pdf

Straight VE. It would be normal to wait a day or so before applying the next laminate, but see what your test result indicates. A laminate will have a different feel on the surface than a puddle or thick layer of just resin.

 

Ok thanks! So you are saying it may feel sticky 24 hours later when I try with it a laminate versus resin sitting in a pot?

Should I be using the "feel sticky" test for knowing if I can laminate for a chemical bond versus there is a need for prep, or do you figure I should go at it based on timing, or some other test?

Jon

 

The touchy feely method works about as good as anything, dig your finger nail into it, while it may feel hard at first, your fingernail still may dig in just a touch.

 

Thanks again!

Update - I did conduct a test, wetting out some 1708 samples with the VE. 24 hour mark, a little sticky but not to the point where it comes off on your hand like PE would, can get a nail in, looks sanely bondable. 36 hour mark still can get a nail in but feeling less obviously sticky; at the 48 hour mark tonight I'm going to laminate over it in a lap and when it cures will try to peel apart and see how it worked. Weather has been fairly warm, averaging 80 degrees where I'm doing this; I mixed it at 1.5% hardener.

One thing that's come to mind and would appreciate anyone's take on the idea, is I'm considering doing my initial layer w/ the VE, followed closely by the 2nd layer using standard ortho PE. The reason for this consideration is I'm really using the VE to help promote the initial mechanical bonding as well as I can, not so much for strength as the PE would be strong enough, and I'd like to buy some additional chemical bonding window; seems like it'd be the best of both worlds, VE bonds to the original structure, get a chemical bond with the next layer of PE, then I have extended my time I can go in between layups and am working with the less expensive resin. What do you think?

Jon