T

tvlawyer

Active Member
Today I started working on tapering the HS810 reinforcement and the HS814 splice angles on the HS front spar. Tapering the pieces requires removing a substantial amount of material. I removed the material on the HS810 with a Vixen file. Man, did that take a long time! Being somewhat impatient and a little bit ADD, I thought I could remove the material from the HS814 with my bench grinder. To make a long story short, the piece hung up on the grinder and I now have an unservicable HS814 with a nice gouge across it. (Replacement already on the way!)

So, how does one properly cut and shape a chunk of aluminum angle? If I can cleanly cut the large chunk of material with some kind of saw or other cutting tool, then I can easily clean and level the edge with file, scotch-brite, etc.
 
Band Saw!

A band saw with a good bi-metalic (metal cutting) blade is what you need. And you'll use it regularly throughout your build. I have an inexpensive small band saw and get good blades from McMaster Carr.
 
After you rough it out on the band saw, use your disc sander to bring the cut up to the line, then finish the edge with the Scotch Bright wheel. Coupla minutes total, max. You need all those tools! Tell your wife we said so...
 
Wood blade OK

DGlaeser said:
A band saw with a good bi-metalic (metal cutting) blade is what you need. And you'll use it regularly throughout your build. I have an inexpensive small band saw and get good blades from McMaster Carr.
Click to expand...

Band saw yes... but a wood cutting blade is OK... the very fine tooth metal cutting blades will clog up with the relatively soft aluminum.

Then use the sanding disk/belt....

This is OK at the normal running speeds of the bench top band saws... even Delta says it's OK..... :)

http://www.deltamachinery.com/index.asp?e=139&p=1459

gil in Tucson
 
tvlawyer said:
So, how does one properly cut and shape a chunk of aluminum angle? If I can cleanly cut the large chunk of material with some kind of saw or other cutting tool, then I can easily clean and level the edge with file, scotch-brite, etc.
Click to expand...
An alternative to the bandsaw and at at times even more efficient is to use is a fiber cutoff wheel fitted to a die grinder. This is the same disc you will use to eventually split the canopy glass with. You can (to a limited extent) even dress the ends of the work by applying a side load to the fiber disc as you would when using a bench sander. Safety first. For smaller jobs such as cutting through sheet up to .032 thick or so, you can even use a Dremel tool or similiar using the smaller cut off wheels designed for them. For cleaner cuts and less strain on your tools, make several shallow passes rather than trying to do it all in one pass.
 
The end of the tale...

After receiving my replacement HS-814 from Van's, I rought cut the shape with an air powered cut-off wheel. I brought the edge up to the line with the disk sander. (I bought the $99 Ryobi disk/belt sander from Home Depot. It looks like that will prove to be a good investment) I smoothed the edges with a couple of passes on the scotchbrite wheel and, voila!, done in 30 minutes and it looks just like it does in the plans.

Thanks to all for the advice.
 
Be Careful

Grinding on aluminum with a bench grinder is asking for a trip to the emergency room. The wheel can explode due to the buildup of aluminum.
I have seen this happen and it is not pretty.
 
tvlawyer said:
After receiving my replacement HS-814 from Van's, I rought cut the shape with an air powered cut-off wheel. I brought the edge up to the line with the disk sander. (I bought the $99 Ryobi disk/belt sander from Home Depot. It looks like that will prove to be a good investment) I smoothed the edges with a couple of passes on the scotchbrite wheel and, voila!, done in 30 minutes and it looks just like it does in the plans.
Click to expand...

Yup, I love my band saw, but if I had to make a choice between it and the sander, I'd keep the disk/belt sander for final shaping of aluminum chunks - I basically wore my Delta machine out building the Valkyrie - great for ending up with a nice straight edge!

(And no, I wouldn't really want to give up my band saw either...)

Paul
 
Brantel said:
Grinding on aluminum with a bench grinder is asking for a trip to the emergency room. The wheel can explode due to the buildup of aluminum.
I have seen this happen and it is not pretty.
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Yep. You make the third person to give me that bit o' advice. So, I took that wheel off the grinder and tossed it.
 
Bench sander good but don?t ...

mix steel and aluminum on the same belts.

The reason is you will push steel into the aluminum part which will cause dissimilar metal corrosion.

I use my $10 14" garage sale bandsaw to cut the pieces, sand them to size on the bench grinder, and finally remove the sanding marks on the deburring wheel chucked in the drill press.

If you can't find a good deal on a bandsaw try picking up a body saw. (They are on sale for $19.99) I have found 101 uses for mine.
 
Brantel said:
Grinding on aluminum with a bench grinder is asking for a trip to the emergency room. The wheel can explode due to the buildup of aluminum.
I have seen this happen and it is not pretty.
Click to expand...

1" benchtop belt sanders (around $100.00) are excellent for shaping aluminum parts, after cutting with a bandsaw or die grinder. No aluminum buildup in the sanding belts.

Finish with 2" pads (available from Harbor Freight) on a 90 degree air driven die grinder, or that special 6" wheel (scotchbrite ?)that's sold for bench grinders.
 
Larry,

As usual, there are a lot of ways to get the job done here. When I started, I used a hack saw to cut all of my angles. I tried the bandsaw, but as one guy said, "my bandsaw couldn't cut a straight line through butter." I know, this is my fault, the saw is not adjusted right. I adjusted it and it cut straight once or twice, but it is out of wack again.

Probably one of the best tools for cutting aluminum angle is a cheap metal cutoff saw. Usually $30-$40 at Harbor Freight. This works really good for simple straight cuts or 45 degree angle cuts, which covers about 90 percent of the angle cuts during the build.

The combination belt/disc sander does a great job of removing metal quickly. A lot better than a file for making rounded corners. I wish I had bought this tool from day one. I found a cheap one on sale at Harbor Freight for $30. It sounded too cheap to be useful, but it turned out to be a good purchase.

Tracy.
 
My vote would be for buying a $89 Delta bandsaw from Lowes/Home Depot. Also buy the Vermont-American 18tpi metal blade they sell for $7.00. After fabricating the entire empennage, wings, and (most of the) fuselage, I'm still on the same saw and same blade and it still cuts through thick aluminum angle like butter. Like others have mentioned, just cut on the outside of the line and finish up with the belt/disc sander and/or a scotchbrite wheel. Good luck.
 
thallock said:
Larry,

I tried the bandsaw, but as one guy said, "my bandsaw couldn't cut a straight line through butter." I know, this is my fault, the saw is not adjusted right. I adjusted it and it cut straight once or twice, but it is out of wack again.
Tracy.
Click to expand...
I've heard this is what happens when the blade is dull. My blade now "pulls to the right" and I just adjust the feed to match - since I'm just rough cutting anyhow. I bought a new blade, but have been too lazy to actually put it on...
 
Yep, that's probably a contributor. I haven't cut too much metal or wood, but several teeth are broken off. The blade is obviously too coarse. I really should try to find the right blade, but I just keep using the hacksaw.


Thanks,
Tracy,
 
Lowes?

thallock said:
The blade is obviously too coarse. I really should try to find the right blade, but I just keep using the hacksaw.
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Tracy, what bandsaw you got? I picked up a 18tpi 59-1/2" blade for my Delta benchtop bandsaw at the local Lowes for $8.

EDIT: Yea, American General, like Steve said! :D
 
Cutting / grinding tools

I have used my circular saw with a hardened blade for cuting hard wood, to cut aluminium angles and other parts. At high speed, I let it eat away the aluminum advancing slowly. Works great, fast and, so far, no harm to the blade and nice sharp, straight, cuts.

For the "fine tuning" I have a belt/disc sander combination on my workbench. You can not do without this when building an RV!!! It allows you to do a "thousand-and-one" grinding jobs, such as: shaping parts, rough deburring, rounding off edges, shaping stringers, grinding to final size, etc. etc.

Regards, PilotTonny
 
Brad,

I don't remember, but I am pretty sure that it is Harbor Freight. I know that several months ago I wrote down the length of the blade and went to HF to get another blade. They only carried one type of blade that fit my machine (62", I think), and it was the same as the blade that I already had. They had several blades in the other size (59 1/2 I think), which I think is more common. I need to check this and try to find another blade. If I can find a blade at Lowes or Home Depot, that would be great.

The one time that I had the band saw setup correctly, it really worked great, so I know how good a tool this can be. It's just very frustrating to use when it starts drifting and you are two inches into the part before you decide it is just not going to come back, and the part is ruined. I just cut the middle block for my flap last week, and it looks like, well, you know.

Thanks for the input, maybe I'll try to fix it this weekend.

Tracy.
 
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