Bow oven design

[SportHunter]

Hey gang, I'm getting ready to build a home use bow oven and wanted to get some input before I start building the oven. I've seen some designs out there but wanted to get any tips or improvements on the basic design.

Many of you have bow ovens, if you were going to refine what you have what would you do different?

What works better, side load or top load? Number of lights preferred and wattage ( 200w x 4 keeps coming up) .
Dimensions recommended. Type of insulation etc.

Thanks for your help.

Paul

[karrow]

my oven is 22wide by 24 tall and 7 feet long. made of 7/16 osb and 2x2 in the corners. mine is plenty wide but other than that size wise is good. I use a air hose form for my recurves. and c clamps for backed bows. mine is a top load with the lights mounted on the lid. which I don't like the lights on the lid. mine has no bottom just concrete floor and no insulation. I use 3 300 watt bulbs and one 200 watt. stays at 180 degrees with very little variation. a timer a thermostat would be a plus.  I think there was a build a long somewhere on here might try a search. lots of ways to go

[fujimo]

i built my box according to binghams plans- served me very well!

[canopyboy]

Mine is 7' long, about 24" tall, and may 16" deep? I made it a front load, bulbs in the bottom with 2x4 supports to hold everything above the bulbs. It is 11/16 OSB with foil bubble insulation on the inside. I put in 7 100W bulbs (I bought a bunch before the regulations kicked in) that I can switch off in groups. With all 7, it will get up to 200 degrees even in the winter. I used one of the inexpensive PLCs to control temp as the Bingham's snap disc seemed to vary 15 degrees between on and off. A small fan is key to keep the air temp inside nice an even. If I only put on one or two bulbs, it stays nice and warm for drying staves, etc.

The biggest problem is the size and weight. It weighs a metric arse-ton and it takes up a ton of room. I mounted it on the wall up against my ceiling to get it out of the way which is better, but loading my heavy form into it up high is less than ideal as well. The guys that integrated them under their work benches seem to have the right idea. If I could change the layout of my shop a little, that's what I'd do. I may still find a way.

[SportHunter]

Canopy, I was thinking of mounting it on the wall but under the bench does sound better after reading your post.

[goobersan]

I plan to change mine to a side load raised up to the same level as my work bench. After a few times setting and picking up a loaded form I realized simply sliding it in and out of position would be a better career move.
I used roofing osb(?) with a foil backing. Lined with 1" foam with the same foil backing. Snap disc from McMaster keeps temps around 176. I can give you a new and used disc if you want to try them. Controllers are easy to put in later when you want to spend $80.
Make yours large enough to accommodate any style, just in case.

[Pheonixarcher]

I built mine according to Binghams specs. The only thing that I did differently was to make the lid tall enough to cover the 200W bulbs. That way, I know if I put something in there that is shorter than the walls, it will clear the bulbs. That being said, it wouldn't hurt to be a few inches taller, as when I glue up a riser block, the screws on the C clamps can be dangerously close to the bulbs. It is also top heavy with the lid open. I also put casters on the side so that when tilted down toward you when standing on end, it is easier to move around. I did upgrade to a digital control unit that replaced the light switch and snap controller.
 
 
 
 
I'll try and get a few updated pics of the improvements.

[SportHunter]

Has anyone used heat lamp light bulbs in their box?

[rockkiller]

Originally posted by SportHunter:
Has anyone used heat lamp light bulbs in their box?

Yep.....got way too hot

[Tim Finley]

Did you use heat resistant wire ?

[SportHunter]

Thanks for all the input, I'll post pics of the finished product when complete. Just a tip for those searching for similar information, search under "hot box" as well as "bow oven", found many more threads to look through.

[bamboo]

I put mine on the wall with a narrow bench for spreading glue on lams

it also has 2" of rigid insulation
when loaded with a form and bow and hose it ramps up nice and slow
 

[fujimo]

very cool set up mike- does look like a bowyers guillotine though   :D    :D

[Buemaker]

I have an old ribbed pipe radiator in the bottom of the box. Since warm air rises I figure it is a little air circulation in the box. The temp control is from an old water heater. No insulation inside, it gets warm enough. I painted it with aluminum paint. Bue--.

[Buemaker]

[Roy from Pa]

I mounted mine on the wall. I only make wood bows so I don't need a real high heat.

 

[Archer Dave]

Just curious why no one puts the bulbs on the bottom. Wouldn't you get a more even thermal stratification in the box since heat rises?

[Archer Dave]

BTW, I like the wall mounted idea.

[bamboo]

my experience is- in a closed system[box] it evenly distributes itself about the system as it reaches thermodynamic equilibrium---

[goobersan]

I like the idea of a fan and ceramic tile by the bulbs. The tiles avoid hot spots and the fan "guarantees" even heat.
After looking at Roy's again..... I'm going to use the door for a staging area at glue-up.