mjshp Posted March 25, 2012 Report Share Posted March 25, 2012 Question, How thick a gap can thickened epoxy fill? The details: S10N #933 Shaping the mast step block is seriously kicking my butt. So rather than spend a second full day shaping second mast step, can I bed the mast step, in a THICK (think 3/8-5/8 inch) bed of thickened epoxy? If not, I welcome any pointers in cutting/shaping the block with out a bandsaw. I have access to a good tablesaw, compund-miter saw, hand plane and belt sander. The compounding problem is I loose the awesome shop I have been working in on wednesday and want to get as much of the shaping/cutting done before I loose access to the "good tools". As always thanks in advance for all the ideas and advice. Quote Link to comment Share on other sites More sharing options...
PAR Posted March 25, 2012 Report Share Posted March 25, 2012 I've filled some pretty big gaps with straight thickened epoxy (no fabrics). Generally, once you get say more then a 1/2" gap, you should start thinking about additional reinforcements, such as fabrics, more wood, a Dutchman, etc. As to your step, I'll let other S-10 builders ring in, but maybe a laminate stack of lumber, carved to shape previously. Quote Link to comment Share on other sites More sharing options...
ChrisObee Posted March 25, 2012 Report Share Posted March 25, 2012 It's cheaper to put the wood scraps in a big gap and use the epoxy for the fine adjustment. Having said that I did bed my mast step in a big pool of thickened epoxy to fill the shallow V below the step. Quote Link to comment Share on other sites More sharing options...
Hirilonde Posted March 25, 2012 Report Share Posted March 25, 2012 I built my mast step with a flat bottom and shaped it on a stationary belt sander. I used a sliding bevel to copy the shape from the bilge to the step to get the V close and then a torpedo level to check that it would sit close to level. It was very easy and fast. Even if you aren't a genius at custom fits by hand you can get the gap a lot smaller than 1/2". Now you are in the very safe range for bedding it into a blob of thickened epoxy. Set it firmly into the epoxy, clean up the excess that oozes out and shape into a decorative filet. Check back several times during the cure to see that is isn't settling crooked and touch up the filet if necessary. Do Not reposition once the epoxy starts to cure. This will break the tack and now your bond is suspect. If for some reason it moves and you don't catch it until cure is setting in it is better to remove it, clean up the epoxy and start again. By rolling newspaper up and taping it with masking tape you can make a tube long enough to go from the partner to the step that is very light weight and can be a big help in aligning the step properly. Quote Link to comment Share on other sites More sharing options...
Howard Posted March 25, 2012 Report Share Posted March 25, 2012 I shaped mine with a small Delta high speed angle grinder, using one of the sanding flap disks. I think it might have been 60 grit or so. Made my mast step from seasoned (read hard) douglas fir and with the grinder, the wood just melted off. To help with the adjustment, you can place a sheet of sandpaper on the bottom of the boat, and either mark the mast step block you are shaping with a pencil or a light dusting of spray-on acrylic paint, then as you fit, just put the sandpaper down, then rub the step back and forth a few times to rub off the paint or pencil marks you made and it will show you the high spots to work on. You should be able to get this down to 1/8th or less gap in less than an hour, even working slowly. I'd think a belt sander, provided you have some type of wood vice to hold your piece, would do the same thing, but just a bit slower. If you use the paint as your indicator, just make sure you give it all a light sanding to get rid of all the paint before you glue it down. Quote Link to comment Share on other sites More sharing options...
Designer Posted March 25, 2012 Report Share Posted March 25, 2012 Michael, You have been given good advice here. Like the Windows operating system, there are lots of ways to do this and they all work. I have fitted hundreds of Spindrift mast steps in my boatbuilding classes and I like to make a good fit rather than using lots of epoxy, and being a teaching situation I can pass on a technique that my students may be able to use in other aplications. I start by setting the mast step in position. Adjust a compass to the greatest gap. Keeping the compass vertical, draw around the perimeter of the step. I then proceed to the band saw. Because we are making a large cut on a small block we need to hold it stable and keep our fingers away from the blade. I set the step on edge on the band saw facing fore and aft. I use a wooden clamp with the two tightening screws. It lays flat on the table and clamps around the step fore and aft. I then tilt the table to the deadrise angle and make the side cut with the whole thing very stable and my hands are well away from the blade. After the first cut, I flip it over , reclamp and make the second cut. It should now be a perfect fit, except that there is a fillet at the keel and the bulkhead. Grind the centerline and the lower forward corners to the fillet radii and you should now have a near perfect fit. Quote Link to comment Share on other sites More sharing options...
mjshp Posted March 26, 2012 Author Report Share Posted March 26, 2012 Update: Started over this morning by gluing up a new block to shape, alternating grain and such (felt very boat builder-y). Don't have a band saw, so I use a combination of pull saw, chisel and upside-down beltsander with 40 grit belt. Using the GB patented compass technique the new step came out great. It's not a perfect fit, but <1/8 should do. Thanks everyone for your ideas, advice and encouragement. Quote Link to comment Share on other sites More sharing options...
Hirilonde Posted March 26, 2012 Report Share Posted March 26, 2012 I don't think Graham has the patent on compass scribing, but it is a great technique 1/8" is a very good fit. You will be glad you took the time to try again. Quote Link to comment Share on other sites More sharing options...
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