Results 1 to 25 of 25

Thread: Glass issues

  1. #1
    Join Date
    Feb 2020
    Location
    Burkesville,Kentucky,United States
    Posts
    9

    Angry Glass issues

    Guys Iíve got a problem.I used Raka epoxy and cloth(6oz.) used it to glass maranti plywood.I wetted it out good so there was no white spots,let it dry,then sanded lightly and applied flow coats.U can pull up the cloth without a terrible amount of effort so I know there is something up.I used the epoxy for scarfs in plywood and that is super strong so I donít think itís the epoxy.The only thing I can think of is it was right in the lower verge of temp in the shop,but it did get hard enough to sand so???Its no peal ply,at least i donít think cause I ordered regular weave cloth and it looks right??any suggestions?

  2. #2
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    17,427

    Default Re: Glass issues

    How long has it been? What temp? What hardener ?

  3. #3
    Join Date
    Nov 2008
    Location
    tacoma washington
    Posts
    1,136

    Default Re: Glass issues

    is the cloth coming away from the epoxy..leaving a distinct cloth pattern behind on the plywood? or the epoxy coming up with the cloth, leaving fairly bare plywood? …

  4. #4
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    17,427

    Default Re: Glass issues

    Blush? Did you wash the hardened pre coat?
    photos would help.
    any chance you have been using a 5/1 epoxy and switched to a 2/1 and got the ratios buggered up?

  5. #5
    Join Date
    Nov 2011
    Location
    Salt Spring Island, BC
    Posts
    6,875

    Default Re: Glass issues

    Quote Originally Posted by the_gr8t_waldo View Post
    is the cloth coming away from the epoxy..leaving a distinct cloth pattern behind on the plywood? or the epoxy coming up with the cloth, leaving fairly bare plywood? …
    Yeah, this.

  6. #6
    Join Date
    Mar 2007
    Location
    East Quogue,NY
    Posts
    19,221

    Default Re: Glass issues

    It is cloth, right? And not mat? ( Mat doesn't like epoxy)

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  7. #7
    Join Date
    Feb 2020
    Location
    Burkesville,Kentucky,United States
    Posts
    9

    Default Re: Glass issues

    It’s is regular weave cloth.I have used all the same epoxy so I’m sure I got it right.I mixed up several batches and it’s not just the one area.The epoxy is pretty much coming up with the cloth.I didn’t let the first coat dry,just wetted it then rolled the cloth than spread more on top.Should I just let it dry longer?it was dry enough to sand so idk?should you not be able to pull it up at all?thanks

  8. #8
    Join Date
    Nov 2011
    Location
    Salt Spring Island, BC
    Posts
    6,875

    Default Re: Glass issues

    So it's a bonding issue.

    Sounds like it's either not fully cured, in which case you would do well to heat it for 24 hours, or perhaps the meranti was contaminated with something that epoxy won't stick too or won't cure well over.

    When you sanded did it plug the paper? If so that may have been amine on the surface, something that is much more likely to happen in a cold and/or damp environment, or it may have just been that it's not cured. Add heat, about 100 degrees.

    Did you wipe the substrate down with something before applying the epoxy? If so what did you use, and did you allow plenty of time for it to evaporate? If you wiped with acetone then immediately coated with epoxy that would slow the curing and affect the bond negatively.

    Properly done and cured it should be tearing off wood.

  9. #9
    Join Date
    Feb 2020
    Location
    Burkesville,Kentucky,United States
    Posts
    9

    Default Re: Glass issues

    Iíve tried loading pics but it wonít let me for some reason.There is a faint weave pattern on the plywood.Yes the part that was in the colder room did have a slick film that plugged the paper a lil but i sanded it off and put it in a room thatís 70 degrees and am gonna let it for a while to see what happens.It seems to be getting harder to pull of
    Attached Images Attached Images

  10. #10
    Join Date
    Feb 2020
    Location
    Burkesville,Kentucky,United States
    Posts
    9

    Default Re: Glass issues

    Ok it worked lol

  11. #11
    Join Date
    Jun 2000
    Location
    Madison Wisconsin
    Posts
    9,506

    Default Re: Glass issues

    Is that the cloth which is peeling that we are seeing, or did you just set a fresh piece on top so that we could see what it looks like when new? If that's the real, peeling fiberglass, then you appear to have some sort of saturation issue with the fabric itself - indicated by the fact that it is still white. Fiberglass fabric is treated with a sizing (volan, silane, etc.) which is what allows resin to saturate it. Those sizings are usually water soluable. Cloth which has been contaminated by exposure to water or severe humidity in storage may have lost too much sizing to saturate properly, and those areas will appear white and not take resin well. There are also sometimes sizings which are not compatible with certain resins. If it doesn't saturate properly, it's often pretty easy to peel off, leaving only a layer of weave-textured resin on the surface and no fibers.

    Stop sanding! You need to learn some basic fiberglassing techniques. First of all, sanding fresh epoxy resin is a serious health hazard which should be avoided before you develop an allergy to epoxy and can't be around it for the remainder of your life. For any large area, it should be allowed to cure for a week or better to lose most of its toxicity before being sanded. On clear finishes, you can also "bruise" new epoxy, creating tiny microfractures down inside the weave, which are ugly and not fixable, if the cosmetics matter. Too much heat from friction with the sander (often caused by plugged up sandpaper) can also do this and fresh resin is more prone to it than fully cured resin.

    Secondly, you do not sand between the initial glass application and the application of resin weave filling (flow) coats. It is not needed and likely to do more harm than good. If you have waited overnight or a couple of days, you should wash it with plain water and a scrub brush then dry it to remove amine blush or any other forms of contamination which may have settled on the surface before proceeding with filling the weave. Solvent washing is seldom needed and another thing which is quite likely to do more harm than good. The best case scenario is generally to add the first filler coat as soon as the cloth layer has stiffened enough that you won't disturb it. The best rule of thumb is to add as many thin filler coats as it takes to completely bury the cloth texture, and then add one more as a cushion for later sanding. Those coats can all be added as soon as the previous one has stiffened sufficiently and it is possible to put them all on that way with no washing, sanding, etc. needed between them. Let that all cure for a week or so, and then sand the surface smooth with a disk or random orbit sander.

  12. #12
    Join Date
    Feb 2020
    Location
    Burkesville,Kentucky,United States
    Posts
    9

    Default Re: Glass issues

    Sorry that was a really bad pic.the cloth is clear but turns white when u pull it up.Thanks a lot for all the posts!i appreciate it.Love this forum,never had so many replies in such a short time

  13. #13
    Join Date
    Nov 2011
    Location
    Salt Spring Island, BC
    Posts
    6,875

    Default Re: Glass issues

    There's something strange going on here. That cloth doesn't look like any 6 oz. cloth I've ever seen, and it doesn't look like it was ever wetted out with anything.

    Also, the meranti looks like it's been around the block a couple of times. It may have some old finish on it.

    Sorry, just relating what I see. I'll shut up if you want me too.

  14. #14
    Join Date
    Jun 2000
    Location
    Madison Wisconsin
    Posts
    9,506

    Default Re: Glass issues

    Cloth which has been properly saturated should never look like that. If peeled off, it would be about as transparent as a plastic milk jug and not look anything like fresh, white, new fiberglass. The weave reminds me of a cloth which one of the canoe manufacturers used to use called "Rov-cloth" with those same flat wide yarns, similar to 24 oz. woven roving, only on a smaller scale and lighter weight. You can certainly try a test chunk, glassing a piece of scrap wood and see what happens, but my suspicion is that your cloth is not compatible with your epoxy - which is unusual, but can happen.

    The ply does look rather "recycled" and there is no telling what sort of surface contamination or previous substances might be on it, but the resin seems to be performing more typically on the ply than on the cloth. The bad news is probably that we know that there is something wrong with the glass to wood bond going on, and it isn't likely to fix itself over time.

    Can it eventually be trusted? Probably not. In order to actually fix things, you would probably need to peel the cloth off, sand the resin to some extent (maybe not all the way down unless it is showing signs of flaking off of the plywood) and re-glassing with different (and pre-tested) fabric.

    P.S. On your next, or similar future applications, you should probably try an approach where you drape the cloth over the hull, dry. Then you roll or squeegee resin into the fabric to saturate it and stick it down. The method of rolling resin on a bare hull and then trying to lay cloth into it and saturate it is kind of risky and may also be part of your problem.
    Last edited by Todd Bradshaw; 02-25-2020 at 04:19 AM.

  15. #15
    Join Date
    Apr 2010
    Location
    South Australia and Tasmania
    Posts
    20,607

    Default Re: Glass issues

    Need more pictures. The one above makes no sense.

  16. #16
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    17,427

    Default Re: Glass issues

    Quote Originally Posted by Phil Y View Post
    Need more pictures. The one above makes no sense.
    none at all

  17. #17
    Join Date
    Feb 2020
    Location
    Burkesville,Kentucky,United States
    Posts
    9

    Default Re: Glass issues

    I dunno Iím having stress loading more pics.I put all the pieces in a really hot room and they really strengthened up.I can hardly pull it off anymore.Even though it was sittin for 48 hr I guess it just wasnít drying right.Btw Iím building the freestone skiff by Jason Cajune of Montana boat buildersIím gonna let it in thereís for a few more days to see what it does then proceed with more epoxy

  18. #18
    Join Date
    Nov 2011
    Location
    Salt Spring Island, BC
    Posts
    6,875

    Default Re: Glass issues

    • Take the pic and upload it to your computer.

      Click on the square "insert image" icon at the top of the reply box.

      Select "From Computer".

      Now click on "Select Files".

      That will give you a box where you can find your photos that are on your computer.

      Click on the photo you want to post. The name of the photo will appear in the box.

      Click on "Upload File(s)" and wait until it is uploaded.

      Click on "Post Quick Reply". The photo won't actually show full size until you post the reply.

      Save these instructions for further use. Once you've done it a few of times it becomes intuitive.



  19. #19
    Join Date
    Nov 2008
    Location
    tacoma washington
    Posts
    1,136

    Default Re: Glass issues

    I'll climb out on a limb here....my guess is that you've got a few things going wrong there. but the two biggies are epoxy starvation, possible coupled with mix errors. the hull looks to be NOT ready for coating with fiberglass( corners should be filled in and rounded over, to allow the cloth to make the transition( without a lot of darts). my approach would of been to roll out, properly mixed epoxy. followed by reapplying same every 5-10 minuets until the woods absorbition slows down to almost 0. only then, roll out the rough cut cloth and wet IT out- all cloth should turn almost clear and roll flat around the corners. I'm not familiar with the design, but from here it looks like you're trying extent that can of epoxy beyond reason. the mixing on the can/bottle should be followed to the letter. If you're having trouble controlling cure temperatures, try tenting over the project and bringing up the temp. inside to around 100degrees it's way easier to do this than trying to control a room's temperatures-and takes a lot less energy to do so
    Last edited by the_gr8t_waldo; 02-25-2020 at 12:50 PM.

  20. #20
    Join Date
    Feb 2020
    Location
    Burkesville,Kentucky,United States
    Posts
    9

    Default Re: Glass issues

    Well Iím just an amateur so advice is appreciated.The wood is new from Boulter plywood so no finish or anything.Was sanded to 120 then coated with epoxy.After it quit soaking and got a lil tacky I rolled out the cloth then saturated with more epoxy.The reason that the first pic doesnít look good is cause that was an over sized piece that need to be trimmed and I didnít pay as much attention to the epoxy out there.My boat designer recommended glassing everything like this then stitching it together.It gets tape in the corners of course
    Attached Images Attached Images

  21. #21
    Join Date
    Jan 2009
    Location
    Narragansett Bay and Approaches
    Posts
    233

    Default Re: Glass issues

    Get it good and warm.
    +70 degrees if you can swing it for 24 hours.
    Should be better.
    SHC

  22. #22
    Join Date
    Apr 2015
    Location
    St. Helens, Oregon
    Posts
    2,087

    Default Re: Glass issues

    Does the design call for glassing the planks before assembling? Not sure I read that right? Seems like that'd impose a lot more stress on the glass/wood interface when you bend it up for the stitch and glue and make the bending a lot harder. What's your design? Some of us busybody types just gotta know

  23. #23
    Join Date
    Jan 2006
    Location
    South of Butter Brook, Norway
    Posts
    784

    Default Re: Glass issues

    If you have to work in a cold shop, preheating the epoxy before mixing in a water bath makes it more runny and makes the saturation easyer.
    Ragnar B.

  24. #24
    Join Date
    Feb 2020
    Location
    Burkesville,Kentucky,United States
    Posts
    9

    Default Re: Glass issues

    Yeah he said to glass before cause it’s a lot easier.The skiff is flat bottom with not any really extreme curves so I think it will be okay

  25. #25
    Join Date
    Feb 2020
    Location
    Burkesville,Kentucky,United States
    Posts
    9

    Default Re: Glass issues

    Ok my problem is solved �� just needed more heat and time.Thanks guys.I might post a pic when(if I ever) get done with it.Wanna use it for fishin this summer

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •