another scraping question

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sluggo
Posts: 244
Joined: Tue Sep 12, 2006 11:17 pm
Location: Vancouver BC

another scraping question

Post by sluggo »

Hi,
I did my first bit of scraping on the inside of the hull today. I understand that it is usually preferred to scrape all of the glue off before using the ROS? I'm finding this a bit difficult. I tried to grind a curved edge onto a paint scraper but it's not the easiest thing to do imo. Getting the curve isn't too bad (ie I don't think the actual shape of the curve is very important), but sharpening the edge after it's been shaped is difficult. I found that the edge simply tends to ride up and over the dried glue. Big drops came off okay but a lot of the "flatter" dried glue has the scraper just sort of gliding over top of it. Any tips on sharpening these blades? I just tried to get a good edge/bevel with some 400 grit paper. Holding the scraper against the paper so that the edge is flat and not rounded is the tricky part. I'm used to using veritas sharpening system for this kind of thing! For the scraping motion, I found that holding the handle at almost a right angle (maybe 70 degrees) to the wood surface was the most effective.

Image

The scraper I'm using is similar to this:
Image

thanks
Doug
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Jim Dodd
Posts: 1359
Joined: Wed Feb 08, 2006 11:08 pm
Location: Iowa

Post by Jim Dodd »

Hi Doug

The glue looks like my first boat ! I scraped and sanded until I was blue in the face ! That was before my first random orbit !

Several thoughts. Sanded glue can end up in the swirl pattern of the sander and show up later under the epoxy. Change discs often, and remove saw dust with a vacum.

I start with 40grit, and then finish with 80 to 100 .

I always keep my center form strapped in. to keep the hull from sagging and deforming while I'm sanding.

I've made my own scrapers , but had good luck with a pull scraper that had several different shaped blades, that are screwed to a handle. These are easily resharpened, with a fine hand file.

Good luck !

Jim
Keep your paddle wet and your seat dry!
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Denis
Posts: 313
Joined: Tue May 11, 2004 8:11 am
Location: Lakefield, Ontario

scraper sharpening

Post by Denis »

try using a metal file at a 45 degree angle

You will have to experiment with the angle up and down but the idea is to take a shaving off as you pull scraper. also try at a bit of an angle as well as straight back

Denis
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mtpocket
Posts: 562
Joined: Wed Sep 08, 2004 2:48 pm
Location: Indiana

Post by mtpocket »

Try something like this:
http://woodworker.com/cgi-bin/FULLPRES. ... DQodMAOGbQ

or this:http://www.homedepot.com/webapp/wcs/sto ... -100659761

I have one like the bottom one and it works really good. I've read where some people prefer the top one.
sluggo
Posts: 244
Joined: Tue Sep 12, 2006 11:17 pm
Location: Vancouver BC

Post by sluggo »

A rounded cabinet scraper is maybe a good idea. I used a flat one for lots of the glue removal on the outside, and they are quite inexpensive.
cheers everyone
AlanWS
Posts: 209
Joined: Thu Mar 17, 2005 4:30 pm
Location: Shorewood, WI

Post by AlanWS »

A gooseneck (rounded) scraper is helpful and cheap. Another useful tool is a surform plane with a half-round blade. Be careful with that one not to take off too much. The best way to use it is to not press too hard, but to skim it quickly over the surface and it will shear off the glue spots. In the narrow bow, I think I just used the blade.

http://www.amazon.com/Stanley-21-299-10 ... d_sim_hi_2

I used just a surform plane and hand sanding on my first boat, which makes me appreciate random orbit sanders.
Alan
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Denis
Posts: 313
Joined: Tue May 11, 2004 8:11 am
Location: Lakefield, Ontario

scraped today

Post by Denis »

We did this one today in about 2 hours using 3/4 inch and 2 inch paint scrapers

Image

Denis
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Denis
Posts: 313
Joined: Tue May 11, 2004 8:11 am
Location: Lakefield, Ontario

paint scrapers

Post by Denis »

I stand corrected. We used a variety of paint scrapers from 1 inch to 2 1/2 inch with the corners rounded off. The 1 inch one is esp useful in doing the bilge areas. I do the glue line first then the middle of the plank until I feel I have a fair curve. The wider ones work well in flatter areas and take a wider shaving. I was teaching two fellows how to use them today and they caught on fairly quickly. Paint scrapers do work best sharp and you need to use a fair bit of pressure on them to make them cut.
If you are simply dragging it back on forth with light pressure you might as well use sandpaper

This wasn't a skill I picked up right away. It took several boats before I caught on to how to do it more correctly

Image

If a full sized image would benefit anyone pls ask me and I will email it to you.

Denis
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