[adamchapman]

Hi all,

I'm making some of those wooden dinosaur skeleton puzzles, but it takes an age to sand down the wisps you get on the edge of cut plywood.

Can anyone steer me towards a cheap supplier of appropriate lasers? The only thing I can find is a seller called "guyoved" on ebay.

Thanks,
Adam

[protomate]

How thick are you trying to cut? The best way to laser cut is using flowing gas not sealed tubes. Most sealed tubes on Ebay are china made systems. They are disposable. You cannot refill them when the gas is depleted. You may get 6 month's out of them even if you do not use them. A well made USA sealed tube has a projected life of 10,000 work hours, but a 20w will run you 4-5k. A refill runs about 3k. I work with laser everyday. I service, repair, design, (and have a really good time frying ants from 10ft with mine). Flowing gas is the way to go and ultimately cheapest.

[adamchapman]

well for the dinosaurs only 4mm ply, but I am looking at making a grandfather clock from 3/4 inch walnut.

With the clock parts, i want to be able to cut all kinds of thicknesses to get a nice curved rebate. Looking at the equations behind laser cutting at http://alumni.media.mit.edu/~yarin/laser/physics.html, it looks like it would be hard to cut half way into different peices of wood because the density of different parts of the tree would be different anyway.

Still i would like to see if the laser would be economically viable for my dinosaur cutting, i can always re-mount the router for clock making

[SkipW]

How thick are you trying to cut? The best way to laser cut is using flowing gas not sealed tubes. Most sealed tubes on Ebay are china made systems. They are disposable. You cannot refill them when the gas is depleted. You may get 6 month's out of them even if you do not use them. A well made USA sealed tube has a projected life of 10,000 work hours, but a 20w will run you 4-5k. A refill runs about 3k. I work with laser everyday. I service, repair, design, (and have a really good time frying ants from 10ft with mine). Flowing gas is the way to go and ultimately cheapest.

Actually, just for the record, Photovac Laser in Ohio will re-gas glass laser tubes. They claim to have had good results doing it and guarantee the tube for 1 year although they say they will probably last longer. Last I heard you are talking about $1200.00 though.

Skip

[MacGyver]

The best way to laser cut is using flowing gas not sealed tubes. Flowing gas is the way to go and ultimately cheapest.

And on what do you base this opinion? In this particular application, I see no benefit to a flowing gas tube other than reduction in price compared to a sealed US-made metal tube... but that price reduction can also be had with a sealed glass tube from China. With flowing lasers you have to get the mix right (if you're mixing it yourself), or you have to purchase pre-mixed gas tanks (not always in great supply, depending upon location). Then you have this big honkin' tank sitting on your floor. After all of that, just buy a cheap eBay tube and be done with it. A 40W sealed glass tube can be had on eBay for <$300.

Most sealed tubes on Ebay are china made systems. They are disposable. You cannot refill them when the gas is depleted. You may get 6 month's out of them even if you do not use them. A well made USA sealed tube has a projected life of 10,000 work hours, but a 20w will run you 4-5k. A refill runs about 3k.

Yes, they're disposable, but even if you get 6 months of working time out of it (somehave been running several years without a loss of power) you're still ahead of the mark. At those prices, no need to refill, just purchase another tube.