Thanks Thanks:  0
Likes Likes:  0
Needs Pictures Needs Pictures:  0
Picture(s) thanks Picture(s) thanks:  0
Results 1 to 5 of 5
  1. #1
    Join Date
    Aug 2008
    Location
    Birkdale
    Age
    51
    Posts
    279

    Default Where did I go wrong?

    Hoping to get some advice on something that didn't work out for me.
    I've been repairing a fibreglass kayak which had split. I epoxied the top and bottom halves back together, then run some new tape around the entire seam. It was then sanded and waiting for flow coat/2 pac. At this point, life and personal issues got in the way, and it sat untouched for 12-18 months. I recently thought about getting it finished, but was concerned that maybe the new tape around the seam was insufficient. I masked up and ran another layer of tape along one side, wet it out and applied the subsequent fill coats. This afternoon I went to remove the masking tape, and as I was pulling it off, I noticed a small section of the new tape seemed to lift as well. I grabbed a scraper and probed at it and it quite easily started to lift off. Once I could get a finger hold, the entire length peeled off like masking tape, with very little effort.
    IMG_0683.jpg
    The tape underneath had been sanded (prior to sitting for 12-18 months) and cleaned down with acetone prior to the last layer of tape going on.
    Any ideas as to what went wrong, and what I can do to remedy the situation, as I'd really like to get another layer of tape on the seam.
    Thanks,
    Chris

  2. # ADS
    Google Adsense Advertisement
    Join Date
    Always
    Location
    Advertising world
    Age
    2010
    Posts
    Many





     
  3. #2
    Join Date
    Feb 2008
    Location
    Eustis, FL, USA
    Posts
    2,270

    Default

    I sounds like amine blush existed and though you sanded (smearing it into the surface) the acetone wipe, doesn't remove it. Amine is water soluble, so a simple scrub with a scouring pad and a few drops of dish detergent in a bucket of water is all that's necessary. Surface contamination, plain and simple. It happens to the best of us. Pull what remains of the tape, scrub the surface good with warm water and a little soap. After this is dry, sand in prep for another layer of tape. Don't use fine grit paper, 100 is about as fine as I'd go, but I prefer a good mechanical "keying", so my usual choice is 40 - 60 grit, to lay down big 'ol scratches, the goo and fabric have to get a good grip on.

  4. #3
    Join Date
    Aug 2008
    Location
    Birkdale
    Age
    51
    Posts
    279

    Default

    Thanks PAR,
    I'm using Bote Coat, so amine blush shouldn't be an issue. The grade of the sanding could have been part of the problem. It would have been down to 240/320.
    Would the fact that it sat for 12-18 months be an issue? It was stored under cover, and would have been exposed to normal daylight, but not direct sunlight. If that's an issue, would sanding back with say 60 grit be ok?

  5. #4
    Join Date
    Feb 2008
    Location
    Eustis, FL, USA
    Posts
    2,270

    Default

    Yeah, those grits are way too fine for a good mechanical "keying" of subsequent coatings. It's not a two pack LPU, just epoxy.

    Even epoxy formulations are are supposed to be blush free, often can blush anyway. It's all about environmental condisions, temperature and humidity mostly. The unreacted amines on the surface are affected by moisture (and other stuff) in the air and can leave a waxy film, once cured, which we call blush. Humid days will cause the worst of it, but something as simple as a open flame, can put enough partly spend hydrocarbons into the air to cause a reaction. My usual recommendation is unless you can really control the environment (HVAC), you should just figure you'll have some level of blush on the surface, that needs to be washed off.

    Reflected UV can still damage epoxy, that's not protected. It takes a lot longer and the epoxy color is the usual "tell". If it's very yellow or hinting at brown, you have UV damaged epoxy.

    It sounds like a combination of things conspired to you off. Unfortunately, I think you know what needs to be done.

  6. #5
    Join Date
    Aug 2008
    Location
    Birkdale
    Age
    51
    Posts
    279

    Default

    Quote Originally Posted by PAR View Post
    Unfortunately, I think you know what needs to be done.
    Bugger.
    Thanks for your help PAR.

Similar Threads

  1. The Wrong Box
    By chook in forum WOODWORK - GENERAL
    Replies: 12
    Last Post: 29th April 2012, 11:51 PM
  2. I could be wrong, but ...
    By Allan at Wallan in forum WOODIES JOKES
    Replies: 1
    Last Post: 13th February 2010, 07:13 PM
  3. What's wrong with this?
    By rsser in forum BANDSAWS
    Replies: 15
    Last Post: 1st March 2008, 10:54 PM
  4. Talk about wrong place at the wrong time....
    By silentC in forum NOTHING AT ALL TO DO WITH WOODWORK
    Replies: 8
    Last Post: 25th October 2005, 11:51 PM

Posting Permissions

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