Blushing

I applied my third coat of epoxy to hull about three days ago, could not get back to work on it fast enough.  I have been sanding between coats as recommended.  However, I went to sand and it is smearing in spots- I am guessing "blush"?  Could it be anything else?  Tempertures did drop again, could this be effecting curing process?.  Night it drops into 30s, day it is in high 50's, low 60's. I know without seeing it it is tough to diagnose, but a little concerned about applying my primer over it if it is blush- will primer adhere to blush?  Plus it doesn't seem to want to sand smooth?  HELP.

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RE: Blushing

Kiz,

First off, what type of epoxy are you using? The types CLC puts in their kits are non-blushing so if you have those I doubt the problem is blushing. If it is a different type and it's blushing it will wash off with soap and water. If it's a non-blushing epoxy the problem is either in the mix, i.e. not mixed thoroughly before applying, or the temperature. You should be around 70 degrees for a 24 hour cure time. Since there are only certain areas that are effected I'd tend to think it was more the mix. As you say, a pic would be of help here. Worst case scenario, scrape off all the areas, clean them with denatured alcohol, wipe clean and dry and re-apply epoxy when it gets a bit warmer.

George K

RE: Blushing

Based on my own experience, I can echo what George is saying.  If you sand too soon before the epoxy is fully cured, you will 'smudge' the epoxy instead of take it off.  This happened to me a few times before I realized that I need to let things cure for at least 4 or 5 days in these temps before touching sandpaper to them.  That being said, I do my filler coats without sanding in between and relying on the chemical adhesion of each coat to the previous one.  You can try some shop lamps of a space heater at night (just make sure you check it every so often to avoid risk of fire) to warm the space up a bit and speed up the curing.

~C 

RE: Blushing

Thanks for the replies so far, it was not MAS epoxy, but the manufacturer claims it is non blushing.  If the mix was off, do I have to scrape of the whole thing? Will the epoxy eventually cure properly over a couple extra days and some extra heat?  WIll try to send pics.

RE: Blushing

I'd say give it a few more days and a little heat to see if it sets up.  I'd try that before scraping off all that time and money. 

~Chris

RE: Blushing

What Chris says. Also, if you've been using this epoxy and haven't had a problem with blushing I would be surprised if it's your problem now. Heat and patience might prevail here.

George K

RE: Blushing

Hey Kiz,

 

I'm also from Chicago. Do you have any pictures of your kayak?

RE: Blushing

Yes I have pics, but they aren't exactly full pictures because it is in my garage.  Just angle shots and diffrent stages of building, just so I can look back some day and remind myself what it took to build.  It's actually been fun.  I don't know how to attach the pics though, if someone can tell me I will attach a few at the risk of embarrassment.  Hope to be done by May 1.

RE: Blushing

Kiz,

Go to www.tinypic.com and you can upload photos from your computer.  Once uploaded, you'll be provided several options for accessing them, one of which is an address (link) for message boards... starts with [IMG] and ends with [/IMG].  Copy and paste that link into your post here, deleting the "IMG" portions, and the http:// remainder will allow folks to immediatly jump to your pictures on that website.

Sample:  http://i41.tinypic.com/2e3vqis.jpg

Select "Resize" at 640 x 480 for message boards - this gives you a photo size that's appropriate for viewing here.

Good luck; look forward to seeing some shots,

Larry

RE: Blushing

I am a total newb when it comes to anything related to boats and I only know what I have read.  I assume you are applying the epoxy over fiberglass on your hull.  I read your post where you said you did not buy your epoxy from CLC.  Did you get your fiberglas from them?  Could it possibly be the fiberglass and/or the epoxy you are using?  Again, I know nothing, but I did read the book, How to Fiberglass Boats, by Ken Hankinson.  It has a chapter about fiberglass types and the finishes and you should use nothing but fiberglass that is specifically made for boats.  Fiberglass has finish coatings and some are not suitable for this type of application. According to the book, the glass cloth used for boat building should have a "white translucent appearance".  Following is a direct quote from the book:  If it does "NOT have this white translucent quality, or otherwise looks dirty or greasy, or has dark colored streaks, patches, or spots, DON'T BUYT IT NO MATTER HOW CHEAP IS MAY BE!  Such material may not have been cleaned or finished, or was not finished completely or properly.  It may not wet out properly and may prevent bonding of the resin to the surface."

RE: Blushing

Hello Jeff, I bought my epoxy/ fiberglass from a boat supplier on the west coast.  The first two coats went on fine and after speaking with CLC and my supplier, it sounds like it needs a little more time to cure properly.  I am in total aggreement about using inferior products.  Cheaper does not always mean bad though.  You have to research the product before using. I know that CLC recommends MAS epoxy and uses other suppliers, which are great products.   However, I did not have a lot of money for this project and cut costs were I could.  I don't believe this supplier is bottom of the barrell and was highly recommeded.   Simply put, when you have more time than money, you have to get creative.  As with this forum, all this proffessional advice from years of experience cost me nothing other than a "Thank You"! Still working on pics.

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