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Nickinoue - n/a
31-Jul-06, 06:15 PM
Hi,

was welding the base for the hull/engine attachment on ma hover when i noticed it was slighly bent in the middle http://hovercraft.org.uk/images/icons/smiley_icons/icon_eek.gif in between where i had welded the 2 welds, they were both on one side and i can see why it would have warped http://hovercraft.org.uk/images/icons/smiley_icons/icon_rolleyes.gif . What i was wondering is how have other people stopped this, i mean u need the power to get the penetration but you dont want it to warp!, would doing it bit by bit and cooling it with water do the trick?

Thanx

Nick

jon_curtis - n/a
31-Jul-06, 07:21 PM
ah no dont cool with water!



give me a call if you want some advice nick

heat distorsion is what you describe as one side of the part cools, it shrinks a little. you can get around this several ways.



take the heat away quick, to minimise the effect, big copper blocks are used in industry.



clamp everything down tight untill cooled, you may need a tooling bed/table to do this on.



be clever in how you weld, i.e. weld one side and then the other so it pulls back into square.



dont get the part hotter than needed to get peneration.



the list could go on.



dont dip cooling weld in water tho, cooling of the weld too quick can cause it to crack NOT GOOD.



hope this helps

cheers

jon



p.s. when its all cooled down you can always find a big hammer and make it straight again?

Nickinoue - n/a
31-Jul-06, 10:31 PM
cheers jon,

Ive been welding for along time but never came across such large distortions before http://hovercraft.org.uk/images/icons/smiley_icons/icon_razz.gif . Anyway now i know and i will try and rectify.

I found this site if anyone else is intrested that shows techniques to try to prevent weld distortion.

http://www.lincolnelectric.com/knowledge/articles/content/di (http://www.lincolnelectric.com/knowledge/articles/content/distortion.asp) stortion.asp

How did the rest of you mamage to make your fan mount without it warping? I mean the pre-made shaft from Ken is 3mm steel mounted to the 1 inch box section----that needs some heat to get it to weld so did you have a problem or was it not noticed? http://hovercraft.org.uk/images/icons/smiley_icons/icon_confused.gif

Nick