I have seen videos, and watched people do it live. For some reason I just can't get it to work. I'm talking about using a saw -- which was designed to make straight cuts in wood -- to make perfectly vertical curved cuts in foam. I have tried using thick saws, and thin saws. Rip saws and crosscut saws. I even tried a Japanese pull saw based on a post from Herb. Every time, when I try to make a curve, the blade tilts away from vertical. I have successfully used an electric jigsaw, but that won't work for my current project. The foam is 2 lb. density EPS that is 5" thick (wink-wink), and my jigsaw blades aren't that long. I need to use a hand saw, but am too scared to come close to the line for fear of making a less than vertical cut. Am I the only one who has this kind of trouble? What is the secret?
I've discussed this with Whit as she has the leaning saw problem also.
frist, trim excess foam from the blank so your only cutting an inch or two off the outline.
second ,, pump the saw up and down like a jig saw when cutting curves, I put my thumb in the handle to hold the saw.
third,, find the correct approch so the saw blade naturaly tilts outward when cutting.
I cut toward myself with my right hand and the blank to my right side
I stay outside the line and if the saw tilts , the undernieth end of the saw tilts away from the line
and I can square up the outline after the cut
hope this helps
Swied, if you have the tools, a grinder or files, you can get a longer blade for a Sawzall or reciprocating saw and file/grind the end to fit your jigsaw. Saw it here on Sway's but can't remember who. It's a great idea and they sell pretty stiff ones that wont bend. Try that and good luck .
ps. No Hotwire?
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I've discussed this with Whit as she has the leaning saw problem also.
frist, trim excess foam from the blank so your only cutting an inch or two off the outline.
second ,, pump the saw up and down like a jig saw when cutting curves, I put my thumb in the handle to hold the saw.
third,, find the correct approch so the saw blade naturaly tilts outward when cutting.
I cut toward myself with my right hand and the blank to my right side
I stay outside the line and if the saw tilts , the undernieth end of the saw tilts away from the line
and I can square up the outline after the cut
hope this helps
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Sounds logical. I'll give it try. Thanks!
[quote="$1"]
Swied, if you have the tools, a grinder or files, you can get a longer blade for a Sawzall or reciprocating saw and file/grind the end to fit your jigsaw. Saw it here on Sway's but can't remember who. It's a great idea and they sell pretty stiff ones that wont bend. Try that and good luck .
ps. No Hotwire?
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I like that idea of grinding down a Sawzall blade. I'll keep that in mind for future projects. Right now I just want to knock this board out.
This is my first EPS board. I'll come up to speed on hotwiring eventually. For this project, I bought a block of foam from an architectural foam place in SD that has experience working with surfboard builders. I made a rocker template out of a piece of 3/4" thick pine, re sawed it in half, drilled a few nail holes and dropped it off at the foam place. They hotwired the bottom and deck curves for two boards for no extra cost. I didn't have an outline template ready, so I didn't ask them to make those cuts. Now, I am contemplating how to make the cuts by hand with a saw.
Note: When I got the fully cut block back, I noticed that there was enough uncut foam available for a third board. When I finish these two boards I'm going to have to figure out how to build a hotwire, so I can get a shape out of the off cut pieces.
Hey Swied,I don't know if this would help, but I got this jig saw blade kit from Harbor Freight for around 5 bucks and the long black blade on the bottom is 5 inches long, other than that all I can say is practice, practice, practice with the hand saw.
Tom
Greg Loehr was the one who talked about modifying the big blades to fit a jigsaw, but that was more to use a wide blade so it didn't wander as much. Unless you're planning on carrying all 5'' of thickness out to rail, you can do a (very) rough outline cut, then do most of your deck roll, and you'll have a much thinner area to cut final outline.
I have had success with a hacksaw blade. Wear gloves so you don’t cut your hands up.
swied - when i started shaping, i was terrible with the handsaw - i had the same problems as you. i found much better luck with the jigsaw. somewhere along the way, i switched back over to the handsaw and much prefer it. it draws clean lines. when doing slab eps blanks, i use a method similar to what MikeDaniel describes. cut your deck dome into the blank before trueing up the outline - make a huge difference compared to trying to clean up a slab outline especially at 5" thick!!! another trick to clean up a cut to make it vertical is to build a 90 degree angle and glue some heavy grit to one side.
on jigsaw blades
i got lots, many to cut 6"+
if you can't find one i'll give you one................herb
Swied,
I cut with a hand saw and then clean everything up with a planer held on its side. when i get to a curve, i cut with more of the end of the saw cause it tapers up there and the narrow width fits into tight corners easier. I never cut exactly on the pencil line, but rather about 1/8" out side of it. the planer cleans everything up afterwards. also, if you hold the planer nice and straight(up and down), when cleaning up your cuts, it will also make the cut verticle if you didn't already do that with your saw. I don't know if you do this already, but I find it works well for me. good luck
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Swied,
I cut with a hand saw and then clean everything up with a planer held on its side. when i get to a curve, i cut with more of the end of the saw cause it tapers up there and the narrow width fits into tight corners easier. I never cut exactly on the pencil line, but rather about 1/8" out side of it. the planer cleans everything up afterwards. also, if you hold the planer nice and straight(up and down), when cleaning up your cuts, it will also make the cut verticle if you didn't already do that with your saw. I don't know if you do this already, but I find it works well for me. good luck
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I usually do something similar. I have a Bosch planer that has an angle attachment. I put the board in my racks so the rail is facing up, and I put the planer on top. I hold the planer so it is kind of floating above the rail, and use the angle surface as a guide. I don't feel confident enough in my ability to freehand cut the verticle edge as you do. I used this method the other night. The problem was that my saw cuts were 1" to 2" off of the rail. I ended up having to mow through a lot of foam to get down to the line. Also, since my blank is 5" thick, I had to cut a rabbit edge. I used a surform to clean up the high side. It ended up working out well, but I was afraid of being too hard on my planer. I remember Mike D. talking about not running your planer for too long or you'll burn up the bearings. I took a lot of breaks. I planed a little, and then surformed a little. I only did one side of the board, and called it a night. I figured that I would get some expert advise from you all before continuing. I like the idea of crowning the deck first. That makes a lot of sense.
I appreciate everyone comments. I'll let you know how it goes.
For what it's worth, this is how it was shown to me on sub 5" thick blanks. Skin blank both sides draw outline and cut out with a Skil saw. Stay 1/8' outside of line and comeback with a small 1/2" dia. round rasp or surform and work it right to the line getting just right. Then, use a router with a collar on the base and a 4&1/2" by 1/2" spiral bit or an end mill. True up the edge using the rub collar to follow the groove you just put in by hand. Anything left over that the bit didn't catch (length) simply sand flush. You then have a machined 90 deg. rail to work off of. I know plenty of guys using this method, It isn't my idea.
ps. Herb, where do you find such long jigsaw blades?
Howzit swied, I use a short shark saw and it never wanders or changes the angle of the cut, maybe trying one of them might work for you. Aloha,Kokua
I shape the blank, so it's easier to cut.[thinner] I cut backwards, with my saw vertical, like a bandsaw, with my outside arm, this allows my body to be over the board, so I can hold the board with my other hand and my eyes are straight over the line. I used to have the bent problem before this. Also when going around tighter curves cut it roughly abt 1 and a half from your line, I cut just on the outside of the line, on it, its easier than cutting away from the line, just mark ure board an 1/8th wider on each side. I also dont like my saw too sharp, cheers H.
Swied,
I'm no master of the handsaw....
but.....
I have all the hot wire stuff...no need to build a rig...maybe I'll just drop off all this hot wire stuff at your place so you can experiment......
hopefully we're getting foam this weekend..........some poly and some EPS.....more misfit blanks for the Lab....seconds or whatever.....it's quality foam...I trust the guy...Fun fun fun!
check your pm
Ray
A router makes a line as clean as your template.
Unless you NEED to use a handsaw.
I like the the clean cut of the router (and it gave me a reason to pick up another tool).
just saw the 5" part. Guess you could still route it and use the groove for a guide. Keeping your saw blade against the foam would help keep it vertical.
A couple of things come to mind here. 1) whats wrong with using a sawzall? 2) if you are cut from the bottom with a jig saw, and you don't cut all the way through....lets say you are 1 -1 1/2 shy....just snap it off. How thick are your rails going to be? You will be doming and droping those suckers anyway. 3) maybe you are not holding the hand saw right, your thumb should be pointing up in the handle, not pointing down like you are trying to cut a 2x4 on a swa horse. 4) so you just get close anyway then you tru it up with the planer. No one ever cuts a perfect outline with a hand saw...I don't care who they are. The planer is the only accurate thing on a surfboard. 5) stop spazzing out, be the foam Jimmy...
I hand saw my outlines, and my cuts got a lot better when stopped trying to hold the saw vertical. Long, smooth strokes with even pressure on the saw, a firm grip on the handle, a deliberate force holding the saw perpendicular to the plane of the board, flexing the blade around curves… and keeping the saw at a low angle, rather than up and down. I find with more blade in the cut you have less wandering of the cutting edge, and a more stable and consistent angle of cut.