Step by Step Building a hydroplane / MRC is up and running

[Bill Huson]

We learn something everyday. Thanks guys. When I was building a fiberglass airplane we used MC (Methelyne Chloride) to clean the waxy substance off the epoxy. Acetone was not too effective. MC is quite dangerous, so the labels say. Anyway, Thanks for your comments.

Smiley

Acetone? MEK? Sure you weren't cleaning the surface hardener wax off of polyester resin? Polyester resin is "air inhibited" meaning it will stay surface tacky for up to a week, so some formulations use a "surface hardener" which is basically paraffin dissolved in acetone which is then mixed (10% by volume) in the resin. Acetone/paraffin doesn't dissolve but is held in suspension and after applying resin it floats to the surface, acetone goes bye-bye leaving a micro-thin wax coat. A bugger to remove.

Not all epoxy resins have a lot of amine blush - WEST hardeners 207 & 209 don't produce a lot if any. The amine blush can be removed by simple washing. One can add a drop or two of detergent, but it is not necessary and soap would require clear water flush after washing.

Like I mentioned, not all resins suffer from blush. Check the website of whatever resin brand you use for tech info. The WEST site has a wealth of info.

[Bill Huson]

deals!

For boat builders who use Cabosil (AKA colloidal silica/fumed silica), micro-balloons, flocked cotton, etc . . . check out Aircraft Spruce

http://www.aircraftspruce.com/

Good prices! Good prices on a variety of resins as well. Even with shipping Aircraft Spruce beats Waste Marine's resin prices.

[Smiley]

........" Acetone/paraffin doesn't dissolve but is held in suspension and after applying resin it floats to the surface, acetone goes bye-bye leaving a micro-thin wax coat. A bugger to remove.".......

Agreed. Sometimes you can never get the surface clean as evidenced by the "Fisheye" syndrome demonstrated by uneven paint coverage over an ill prepared surface.

A neat trick to eliminate the above problem is:

Use dacron or nylon cloth layed down on the surface you have applied the resin. It cures, the waxy coat is on top of the dacron cloth. Peel the cloth away and you have a perfectly clean surface, wax free. You can now prepare the surface to its final condition.

Smiley

[Bill Huson]

peel ply . . .

used in vacuum draws and vacuum/infusion layups. I know a few folks who have use peel ply on open layups top achieve that nice contaminant free finish, but I haven't tried it. Like Jethro Gibbs I find hours of lonely, peaceful wet sanding and such very therapeutic.

[blueskyracer]

used in vacuum draws and vacuum/infusion layups. I know a few folks who have use peel ply on open layups top achieve that nice contaminant free finish, but I haven't tried it. Like Jethro Gibbs I find hours of lonely, peaceful wet sanding and such very therapeutic.

I agree Bill. Therapeutic for sure and with lots of water I have no problem with clogging paper as long as the epoxy has cured for 3-4 days.

[Raymond]

Our only large project experiance was under pressure of time so...we did not let it cure byond 48 hours before starting the sanding (dry) process and then we sanded to what we thought was when that first layer of expoxy was all but sanded off and then layied anouther coat then sanded flat ready for primer and paint.

We now know the errors of our rushed ways.

[blueskyracer]

Our only large project experiance was under pressure of time so...we did not let it cure byond 48 hours before starting the sanding (dry) process and then we sanded to what we thought was when that first layer of expoxy was all but sanded off and then layied anouther coat then sanded flat ready for primer and paint.

We now know the errors of our rushed ways.

I use to rush it and get frustrated when the paper would clog after 10 seconds. So the next time, something came up after I had applied a coat of epoxy amd I did not get back to it for 4 days. Low and behold the stuff was no problem so I figured it was not full cured before. Have never had a problem again just use lots of water in my hand held spray bottle and make sure it is fully cured.

[krazy karl]

Therapeutic

used in vacuum draws and vacuum/infusion layups. I know a few folks who have use peel ply on open layups top achieve that nice contaminant free finish, but I haven't tried it. Like Jethro Gibbs I find hours of lonely, peaceful wet sanding and such very therapeutic.

Kind of like reloading rifle, pistol and shotgun shells.

kk

[blueskyracer]

Kind of like reloading rifle, pistol and shotgun shells.

kk

Yup what ever works for you

[krazy karl]

Sanding

Yup what ever works for you

I am building a boat too, so I have a ton of sanding in my future. I have also found that giving the epoxy enough time to set up completely will make wet sanding a lot easier. I usually put a garden hose above where I am working and let it trickle water over the area I am sanding.
kk

[blueskyracer]

I am building a boat too, so I have a ton of sanding in my future. I have also found that giving the epoxy enough time to set up completely will make wet sanding a lot easier. I usually put a garden hose above where I am working and let it trickle water over the area I am sanding.
kk

You must shower at the same time

[RLR]

Mike, Great job

And here all these years I thought it was the boat fairy that brought those boats to my trailer. Can't say I am disappointed after seeing your work here on the site.

Thanks for your efforts in the boatracing communities. You have done much to be proud of, but after watching and looking at your posts, humble is the watch word.

Thanks to you Mike, and Mrs. Bluesky

Ray

[Bill Huson]

I am building a boat too, so I have a ton of sanding in my future. I have also found that giving the epoxy enough time to set up completely will make wet sanding a lot easier. I usually put a garden hose above where I am working and let it trickle water over the area I am sanding.
kk

Try a scraper - as in Red Devil. I have several and an 8" fine cut mill file so I can resharpen the scraper edge every few minutes. Scraper removes high spots (runs/sags) in a jiffy! I file the corners off the scraper blade just a wee bit to keep them from digging in.

Cabinet scrapers work well too.

[Dave M]

Removing Waxy Stuff

I got this tip from a boat builder too.

Once cured (West Sys) wash with vinegar. It removes the wax and amine blush. Means put it on a cloth and commence scrubbing. I tried it once, worked decent.

I honestly have not had any of the troubles I see others posting here with the cure times. I use the slow hardner and have never had an issue with it curing overnight. I tend to keep tha shop between 60 and 70 when working and try to keep it 60 and above over night. I am always sanding the next day. Now that nasty Poly or Vinylester resins.... yup. if you don't nail the mix with MEKP in the ballpark range... it will never cure. And it sands a lot worse than Epoxy Resins.

The worst problem I have with cureing epoxy is the pot life being to short. When doing some things the normal soup cans don't let enough air in the mix to keep it from Exotherm. I cut is real close some times.

[blueskyracer]

Latest progress. Put trim strips down the tunnel and have been setting nails flush and filling in deep staples with filler. Now there are a tons of options for filler so I won't even touch the subject but to say a lot of different thing work. Just keep it all flush with the bottom and if it is close the epoxy coat will take care of most small imperfections.

I would like to add that it would be impossible or not affordable for me to take and keep the shop at 60 during the winter when the temp outside is 0 degrees so I give the epoxy 3-4 days to cure during the winter. During the summer I use the slow hardner and make small batches or it will go off to soon. If you like to watch it smoke than make big batches.