Day 3 Cutting
the steel
3rd and 4th
Day 3:
Cut ten more pieces for webbing from sheets
3 & 4. Free-handed curved sections close for
minimum grinding time. Only 8 hours including
copying blueprints to steel, we're getting better!
(Shown at right: paper cut-outs on a proportional paper, 1x2)
22 cut pieces ready for grinding. The stack is only 6" high but weighs over 1500 lbs!

The biggest problem we had working with this plate was the fact that it was not cut square! So there was a lot of trimming involved, which used up a lot of time. As amateur carpenters, we only assumed they would be square. ( ASSUME=ASS out of U and ME! ) In the future, we'll make it a point.

We're no experts when it comes to plasma cutting,
but here's a few things we learned using one:
-Always brace you arm(s) for stability. It's amazing how quickly it cuts errors!
-Don't use a plasma cutter to 'trim' thin sheaves of steel off edge, unless
you like replacing tips after every cut!
-If you need to cut a straight edge, do like we did. Make a little cart
to mount the gun on, with wheels. You can see it in some of the
photos. It remains at a constant hieght, and along a straight flat bar, perfect!
-Work up to a constant speed just below where it can't penetrate fast enough
to cut right through. (Use a practice piece of plate for this! ) This way the
steel can't blob up and it makes for a very clean cut, and less grinding.
-Freehanding, even with the cart, is difficult. You have to look at the beam
and near it to see where you're going. I used a #5 shade and don't recommend it.
The marked line is easier to see but I had to move my eyes around constantly to
prevent a nasty case of 'flash' later on! ( Flash is a 'sand in your eye' feeling that
welders frequently get, that lasts for hours. Not pleasant!) Try #6 or #7 filters first.
-If you have no hand-eye co-ordination at all, I would recommend building a
motorised jig to attach to the cart via a piece of greased 'ready-rod', with a variable
speed control.( Look in hobby shops) All you would have to do is hold the trigger
for the cutter down with one hand and the motor control with the other. We're
thinking about doing this for cutting the large hull plating.

Bend that meter!