Best technique for Perfectly smooth surfaces?

[lmannyr]

So I got a 5 gal bucket of resin, hardner, 7 in rollers, 3 in rollers, acetone, rags, measuring, carb-o-sil, for about 150 bucks.

Now I'm looking for advise on how to fair out the surfaces. By hand, polisher, blocking.... why and how?

I've read it's best using the blocking method. Question is, how do I block the contour of the hull?

I can't find any MAJOR stores that carry sanding blocks. Where should I look for these types of tools.

Thanks...

 

[drewpster]

Re: Best technique for Perfectly smooth surfaces?

I have the best luck first smoothing and shaping with a power sander. An orbital works best if you do not have access to a good air compressor. Sand the hull using the orbital and 36 grit paper to get a rough shape. When the the resin gets close to the contour you want, sand the low spots and fill them with epoxy filler. Sand the filled sections down with rough paper until the surface looks fairly uniform using a slightly higher grit. (60 or 80) Then when the surface gets close to level use 150grit to smooth the surface further. At that point you should be getting close to blocking.
I made all my sanding blocks except one rubber one I use for wet sanding. Basically I have used everything from cut 2x4ers to pieces of broken paint sticks to block sand with. If you have a curved surface, a piece of luan cut to a bendable length works well to sand curves. I countersunk some screws through a piece of luan into a couple of cut broom handles to make handles on the luan block. I used staples to secure the paper to the board from on top. (don’t staple paper to the board through the bottom, causes scratches like hell, staple the paper to the board through the top of the board into paper rolled around the end of it):redface:

 

[ondarvr]

Re: Best technique for Perfectly smooth surfaces?

What is it you're trying to do? Resin filled with cabosil is very difficult to sand and has little strength.

 

[lmannyr]

Re: Best technique for Perfectly smooth surfaces?

fair out the interior for glossy paint...


thanks for the elaborate reply.

 

[ondarvr]

Re: Best technique for Perfectly smooth surfaces?

You would be much better off using a sandable filler designed for that purpose. Resin with cabosil will be a nightmare to hand sand with a block, plus the surface will stay tacky unless you use wax in it, washing with acetone will help to remove the sticky surface, but....

Now that you have the resin, get some micro ballons (they go by different names) and add them to the resin along with some cabosil, this will make it much easier to sand. If they'll let you take the resin back, then do it and get a sandable filler.

 

[lmannyr]

Re: Best technique for Perfectly smooth surfaces?

Opps

 

[Lakeland Bob]

Re: Best technique for Perfectly smooth surfaces?

These guys are located in ST.Pete and are very giving with their knowledge. Their website www.fgci.com will let you order a free catalogue and they have EVERYTHING including sanding blocks.

If the area is not too big you can cover the fresh laid filler with saran wrap and smooth it out over the top. The surface will be shinny and smooth - if you got out all the wrinkles.

I agree you should add micro ballons to your filler but wear a mask as they are very light and you could easily inhale them. You can make up a batch ahead and only add hardener when you are going to use it. If the container is tight it will last upto 6 months.

 

[drewpster]

Re: Best technique for Perfectly smooth surfaces?

I have used epoxy resin cab-o-sil and microballoons to fair the deck of my old tug. I am a novice and when I started the job I knew absolute zero about the task. I used what I learned in here as well as advice from the resin maker.
Looking back I would have done it a little differently.
First make a test batch of your compound. I first used the ratios recommended by the resin maker. It yielded a very thick compound that was difficult to spread. After playing with the mixture awhile I found what worked best for me.
Second, schedule your sanding times closely with the cure time of the resin. Unfortunately for me, work often prevented me from sanding the cured mixture until nearly a week later. In the heat of the summer a week is too long. It made sanding very difficult.
Third, prep the surface to be faired completely before starting application. I highly recommend any prep work or repair to be done completely without exception before starting.
That means have everything ready, including all the supplies you will need. Have enough resin, hardener and filler. Have plenty of mixing pots, stir sticks, gloves, spreaders ect. It is a real pain having to stop and go get more stuff.
The ideal situation would be to have all the repairs and initial prep work done. Then apply the fairing compound, mixed to a usable ratio, to the entire surface to be faired. Then start the sanding as soon as the resin cures to a sandable state.
You can see some bits and pieces of my fairing job in the links below. Truthfully, it is not a job I ever want to have to do again, but I am very happy with the result.