My Official build thread. 27 1/2’ GA

[Todd j]

Not ready yet!

[Todd j]

I’ve been rolling  unthickened epoxy on the hull.  I’m having a hell of a time fighting runs.  I’ve even come back and rolled it again.  On top of that I don’t seem to get much coverage and can still feel the glass weave.  Any pointers?

[Brian.Dixon]

I’ve been rolling  unthickened epoxy on the hull.  I’m having a hell of a time fighting runs.  I’ve even come back and rolled it again.  On top of that I don’t seem to get much coverage and can still feel the glass weave.  Any pointers?

There are several possibilities.  One is coat thickness.  Use a short-nap foam roller - the red barber pole striped "adhesive rollers" or the yellow "adhesive rollers" from System III or Fiberglass Supply in Washington do a great job of applying epoxy and keeping the coat thin.  Also, roll on as little as possible with each coat, re-rolling in opposing directions to get each new patch of epoxy to cover as much region as possible, then use a foam brush to tip off the coat (remove bubbles and smooth the epoxy).  If that doesn't work, then viscosity of the epoxy may be the issue.  Brand of epoxy and temperature are the main factors here.  For example, I know System III works well in all temperatures, RAKA is a little thicker if I recall and may make a better choice ... Aero Marine is on the thin side and may tend to run.  You may also experiment with mixing really well, letting the mixed epoxy sit in the cup for 3 or 4 minutes, then mix again and pour into your roller pan.  This will allow the epoxy to just begin to set a bit while it's in the cup, then when it's poured into the roller pan it then has a lot of surface area and cools off.  Hopefully the result is that after rolling it on the boat, it'll cure quicker and run less.  Another factor with viscosity is the ambient temperature - if the weather is warm, the epoxy will be thinner and more likely to run.  You may want to wait until it's dark outside and cooling off before you coat the boat much.  Or get up early enough in the morning to get a coat on and curing to the sticky 'green' stage before the day starts warming up.  FINALLY, the cure-all for runs is the use of a sharp carbide scraper - Don't try to fix them with sanding.  The scraper will take the runs off flush with the remaining epoxy where sand paper will sand the thin epoxy around the run just as fast as the run, resulting in the removal of your epoxy coat around the runs .... bad juju....

Let us know how it goes....

Brian

[Todd j]

I rolled on thin and went all over the panel and and knocked the bubbles down with a foam brush.  It looked great for several hours then started to sag in spots again. The bottom looks great and is about Ready for graphite.  At best the sides are probably a 25’ finish.  I hope I can do better than what I’ve got now.  I should put one more coat of epoxy on the sides.  I don’t want to sand it all off.  I se what damage I can do with the scraper maybe tomorrow after it hardens up

[Brian.Dixon]

Maybe as a help to others, you might post the brand and product of epoxy that you are using?  And what temperatures are you working in?  Worst comes to worse, just keep scraping the runs smooth with a carbide scraper and adding more thin layers until the weave is filled.  In any case, it sounds like either your epoxy viscosity is low or the hardener's not kicking fast enough.  Note that you CAN ever-so-slightly round up on hardener, but if the brand offers a higher speed hardener (designed for cooler shop temperatures), you might consider getting some until the more vertical epoxy coatings are done.

Brian

[Todd j]

It’s ebond.  80 degrees and heating up.  60 minute hardener.  I have some 30 left. Maybe I will try it next

[Rbob]

Todd,
I had trouble with runs also, I am nor sure what rollers you are using but try the cigar high density foam rollers and press down firmly when rolling, you will be surprised how far you can go.

On my sides I added a little bit of silica which helped a bunch.

No tipping required.

I have used different brands cigar rollers but these are firmer:
https://www.lowes.com/pd/WHIZZ-Cabinet-and-Door-6-Pack-4-in-Mini-Foam-Paint-Roller-Cover/3026938


Bob

[Brian.Dixon]

It’s ebond.  80 degrees and heating up.  60 minute hardener.  I have some 30 left. Maybe I will try it next

Yeah ... your hardener is a bit slow.  You should aim for 20-30 minute stuff for warm weather and just mix and apply smaller batches at a time.  Once the epoxy is rolled thin on the boat, it's got a huge surface area to dissipate heat while it cures and it'll cure slowly compared to when it's in a roller pan.  Get it on the boat fast, then take your time to roll it as thinly as possible.

Brian

[Todd j]

It wasn’t quite as bad as I thought.  It appears that I am seeing small flaws under this new coat of epoxy.  When it is shiny it has great depth.  It throws off the eye.  With a little roughing up it looks like a rough orange peal.  I’m shooting for a 2-3’ foot finish.  All that said I do have a question
   Can I put the final coats of graphite epoxy directly over the fairing compound and continue with light fairing between coats? I am using white glass bubbles not the purple.  I’m not sure if I should expect it to completely cover or not

[Todd j]

Todd,
I had trouble with runs also, I am nor sure what rollers you are using but try the cigar high density foam rollers and press down firmly when rolling, you will be surprised how far you can go.

On my sides I added a little bit of silica which helped a bunch.

No tipping required.

I have used different brands cigar rollers but these are firmer:
https://www.lowes.com/pd/WHIZZ-Cabinet-and-Door-6-Pack-4-in-Mini-Foam-Paint-Roller-Cover/3026938


Bob


When I say tip, all I am doing is smoothing out the bubbles.  I am using grey 1/4” Knapp adhesive rollers.  I think I will try adding some cab-o-sil to my next batch and use the 30 minute stuff

[Rbob]

Todd,
I though I replied from work but this caught my attention:

" I am using grey 1/4” Knapp adhesive rollers"

Sorry for the bluntness, but ditch the 1/4" roller, get the whizz 1/8" foam Brian is suggesting  or (my opinion) get some cigar 4" cigar high density foam rollers I suggested.

Not the ones for latex.   

 

[Todd j]

No worries is that the one you put the link to above?

[Rbob]

yes

[Todd j]

Questions on the spray rails??
 1) at 5” aft of bow where spray rail starts, Will a screw really reach the stem?
 2) do the auxiliary spray rails start at the same point? Or should they join each other meeting at the fairbody? 
 
Thanks, I’m anxious to cut something again.  Been working more hours than I like and my boat building is falling behind.  Now it’s archery season and the build will further slow. 

[Brian.Dixon]

Questions on the spray rails??
 1) at 5” aft of bow where spray rail starts, Will a screw really reach the stem?
 2) do the auxiliary spray rails start at the same point? Or should they join each other meeting at the fairbody? 
 
Thanks, I’m anxious to cut something again.  Been working more hours than I like and my boat building is falling behind.  Now it’s archery season and the build will further slow.

- Yes, you can use the graphite epoxy for fill coats on top of faired fiberglass.  Most prefer to just roll on clear epoxy for a couple of fill coats (faster, no mixing), then when reasonably smooth, light sand and finish with 2 coats of graphite epoxy.

- Without looking, I can't remember how far back the spray rail starts from the bow, but if it's far enough back for the screw to miss the stem .... move it forward

- Both auxiliary spray rails and main spray rails are definitely a "close enough is close enough" kind of deal.  If you've got them going right to the bow, or stopping several inches short .... it's fine.  No need for overthinking on either of these.  Spray doesn't really climb up the hull that far forward.

Hope that helps!

Brian