Selfmade Lavalamps - Feedback

Thanks

I'd like to say "Thank you very much!" to all those people which have contributed their experiences to this page and make it easier for others which try to built a lava lamp on their own.

English If you want to share your own experience or want to ask a question, please send a email to email-address listed on the root page of my home-page.
Deutsch Wenn Sie eigene Erfahrungen beitragen möchten oder Fragen haben, senden sie bitte eine EMail an die EMail-Adresse welche auf der Startseite meiner Homepage aufgeführt ist.

From: Jason Liang (chiahl+AT+pacifier.com)

Why don't you try to use benzyl benzoate instead. As an ester it has a lot less water solubility. Besides it also has a higher density 1.112 compares to benzyl alcohol's 1.045. Therefore you can put a bit more salts and may sodium benzoate to kill germs. Just a thought. I work in a benzylbenzoate producer. If you do try please let me know your results. Benzyl Benzoate is not difficult to buy and it is nontoxic and is even used in gums. If you have trouble to get it, e-mail me your address I might be able to send you a samle sample.

From: Ephraim Grdff (uzs2e5+AT+ibm.rhrz.uni-bonn.DE)

	Subject: Lavalampe - Erfahrungsaustauch

Zum Thema Eintruebung:

Ich habe auch ein gewisses Ausflocken bemerkt. Der Niederschlag liess sich auch nicht abfiltrieren. In normalem Kochsalz sind meines Wissens nach eine ganze Reihe an Ionen, die allesamt Ausfallen koennen. Von daher werde ich es mal mit hochreinem Natriumchlorid versuchen. Falls es klappt mail ich dir nochmal!!

Zur Farbe:

Fuer den Benzylalkohol eignen sich wunderbar die Edding-Refill-Farben (keine Entfaerbung, sehr geringer Verbrauch) und fuer das Wasser eignet sich ganz normale Tinte (ich habe es mit rot und blau versucht, entfaerben sich aber ein wenig nach einigen Wochen).

Zu meinem Problem:

Ich habe die Tarierung mit Salz relativ genau hinbekommen, allerdings war die Oberfaechenspannung von dem Alkohol so groß, daß er sich zu einer großen Kugel geformt hat und dann als ganzes immer irgendwo (je nach Salzgehalt mehr oben oder unten) in der (0.7l Schweppes-) Flasche schwebte. Es dauert auch sehr lange, wenn man einmal mehrere Kugeln durch Schuetteln erzeugt hat, bis diese sich wieder vereinigen.

Wenn die Lampe dann noch relativ lange (1h) an war klebte die komplette Kugel oben, bzw. unten wenn ich nur eine 20W-Gluehbirne genommen hatte (statt 40W). Ich habe darufhin an den oberen Flaschenrand Eisbeutel gehalten und es kam wenigstens etwas Bewegung ins ganze - zwei bis drei stabile Kugeln, die allmaehlich auf und ab wandern, aber nichts von langen 'Faeden' die sich auseinanderziehen und sich teilen um dann neue Kugel zu bilden, die aufsteigen und dann wieder in den Pool fallen usw...

Kennst du einen Zusatzstoff mit dem man die Viskositaet oder die Oberflaechenspannung des Benzylalkohols erniedrigen kann (Ethanol habe ich schon versucht -> geht nicht!) ?

Wie kann man einen besseren Temperaturgradienten erreichen (ist die Glaswand wohlmoeglich zu dick?)?

From: stormoen+AT+sparc.isl.net (Stormoen MD)

	Newsgroups: alt.drugs
	Subject: Lava Lamp Plans Here.
	Date: 13 Jan 1995 08:08:15 GMT

I've had SEVERAL requests for the plans, so here they are.

Sorry, I guess I lost the name of the guy who gave 'em to me. (I recieved two versions, and I liked this one best).

WARNING!! This electronic document deals with and involves subject matter and the use of materials and substances that may be hazardous to health and life. Do not attempt to implement or use the information contained herein unless you are experienced and skilled with respect to such subject matter, materials and substances. The author makes no representations as for the completeness or the accuracy of the information contained herein and disclaim any liability for damages or injuries, whether caused by or arising from the lack of completeness, inaccuracies of the information, misinterpretation of the directions, misapplication of the information or otherwise.

Please note: The information contained in this electronic document can be found in the 1992 Edition of Popular Electronics Electronics Hobbyists handbook, published annually by Gernsback Publications Inc, USA.

Inside a lava lamp are two immiscible fluids. If it is assumed that fluid 1 is water, then fluid 2 must be:

insoluble in water;
heavier than water;
non-flammable (for safety);
non-reactive with water or air;
more viscous than water;
reasonably priced.

Furthermore, fluid 2 must not be:

very poisonous (for safety);
chlorinated;
emulsifiable in water (for rapid separation).

In addition, fluid 2 must have a greater coefficient of expansion than water. Check a Perry's handbook of Chemical Engineering, and the above list eliminates quite a few possibilities.

Here is a list of possible chemicals to use:

benzyl alcohol (sp.g. 1.043, bp 204.7 deg. C, sl. soluble);
cinnamyl alcohol (sp. g. 1.04, bp 257.5 deg. C, sl. soluble);
diethyl phthalate (sp. g. 1.121, bp 298 deg. C, insoluble);
ethyl salicylate (sp. g. 113, bp 233 deg. C, insoluble).

If desired, use a suitable red oil-soluble dye to color fluid 2. A permanent felt-tip pen is a possible source. Break open the pen and put the felt in a beaker with fluid 2.

It is recommended to use benzyl alcohol as fluid 2. (Caution!! Do not come into contact with benzyl alcohol either by ingestion, skin, or inhalation.) In addition to water, the following items will be necessary:

sodium chloride (table salt);
a clear glass bottle, about 10 inches (25.4 cm) high;
a 40 watt light bulb and ceramic light fixture;
a 1 pint (473 ml) tin can or larger;
plywood;
1/4 inch (0.635 cm) thick foam-rubber;
AC plug with 16 gauge lamp wire;
hardware;
light dimmer (optional);
small fan (optional).

The performance of the lava lamp will depend on the quality of the water used. A few experiments must be conducted to determine how much sodium chloride is necessary to increase the water's specific gravity. Try a 5% salt concentration first (50 g of salt to 1 liter of water). Pour the red-dyed benzyl alcohol mixture in a Pyrex beaker. Add an equal or greater amount of water and heat slowly on a hot plate. If the benzyl alcohol floats to the top and stays there, decrease the salt concentration. If it stays at the bottom, add more salt.

Construct the lamp by fastening the ceramic lamp fixture to a 5 inch (12.7 cm) diameter piece of plywood. Attach the lamp wire to the fixture. Screw in the 40 watt bulb. Cut one end off the tin can, remove its contents, and clean thoroughly. Drill a hole in the tin can for the wire to go through. Invert the can over the bulb (open end down) and affix to the plywood with epoxy. Cut a round gasket from the foam-rubber and fit it into the ...

From: bruder

	Date: Mon, 20 Jul 1998 12:31:28 -0400
	Subject: lava lamp

I had been given a simplex model 8200 N to repair. The owner topped off the bottle with plain tap water and the lava would not rise. I got on the internet looking for info and found a site that said the contents were pattented(wouldn't you think after 30 years it would expire?), but the fluid was probably a mixture of colored benzyl alcohol ( or a related aromatic alcohol) and colored water containing enough table salt (sodium chloride, NaCl) to balance the density of the lava when heated. So, I took out a little solution and let the lamp warm up 2 hours. Then I added slowly (waiting a while between additions) a saturated salt solution made by adding a little water to a lot of table salt and boiling. Use the salt solution hot. If the lava stays at the top too much, you have added too much salt. Add hot water and wait for the soln to equilibrate. Go back and fourth with the salt(has more effect per unit volume) or water until you are happy with the lava show. Give the thing time between adjustments to stabilize. Its a balanceing act between the close density of two immisible solutions and a temperatrue gradient from the bottom of the lamp to the top. The other thing that could be fixed is in the case of a hazy water solution is to drain the water and replace it with new salt solution(~ 4.8% weight to volume in distilled water to start, then adjust) containing a water only soluble dye.A little BHT or BHA would inhibit growth of bacteria which cause haze.

Wm. Bruder

From: "Pascal" <pascal.truan+AT+urbanet.ch>

	Date: 	Wed, 31 Mar 1999 21:35:01 +0200
	Subject: Lavalamp

Hi Robert,

First I want to thank you for your gathering of informations about lavalamps. I am a chemistry teacher in Switzerland and I am trying to make lavalamps with some students of mine. We used exclusivly informations from your web page!

We used benzyl alcohol and cinnamyl alcohol as the lava and salted water as the aquous phase. Here are some results:

1. Effect of the nature of the lava:

Cinnamyl alcohol seems to be more viscous and "sticky". This is very nice because there is always some lava remaining stuck in the bottom of the lamp so it forms several bubles and never one only buble standing in the middle of the lamp. Besides, cinnamyl alcohol is already a bit colored (yellow) and we don't need to color it more.

Benzyl alcohol works well too but we sometimes have one only buble standing in the middle or at the top after 2 or 3 hours. The very best result was obtained with a mixture (about 4:1 cinnamyl:benzyl). In fact, it gives an incredible lavalamp producing 5 to 10 bubles continously during hours and hours.

2. Effect of the shape of the bottle:

Definitly, best results are obtained with long and thin bottles. This seems logical since it allows a far better temperature gradient. When the bottle is too wide, there are many risks for the formation of one only very slow buble

3. Effect of the colorant:

We colored benzyl alcohol with either water resistant pen ink or with alimentary lipophilic colorants. In both cases, it seems to me (I'm not sure at all) that the colorant is a bit problematic as it acts as en emulsifiant. As those colorants are often not very pure, we tried to extract several times the possibly hydrophilic part of them. Il was very boring to wait every time for the mixture to sediment but it helped a lot.

4. Most important problem:

The most important problem we had (and we still have) is when we stop the lavalamps. When cooling down, the aquous phase becomes an opaque emulsion. This is not beautiful at all. The emulsion desappears after about 20 hours when the lavalamp stays cold. When we swith it on, it takes about 45 min for the water to get clear again.

Do you have any idea to solve this problem? It seems that it is due to salt but this sounds stange because salt is rather knowned as an emulsion breaker!!?? Tomorrow, we'll try to add a very littl bit of surfactant.....

5. Use clean bottles!

We had problems with lava sticking too much to the glass and not going up. In fact, it was probably due to the inner part of the bottle thar was not clean enough. We cleaned all bottles with soap and then sodium hydroxide solution and the problem was away.

I'm sorry not to be able to give you more quantitative informations about lava mixtures and salted solution but we worked quite "instinctively" and "empirically" without measuring quantities. Anyway, if you want more details, fell free to email me and I'll answer with a great pleasure if I'm able to.

6. Try to get a good temperature gradient!

There was one lavalamp made in quite a wide bottle that didn't work well at all. The lava took very long to get up and then stayed up because the whole bottle was hot and the temperature gradient was insufficient. We fixed the problem by reducing the opening between the light and the bottom of the bottle. This way, only the center of the bottom was heated and the temp gradient was much better. The result was almost magic and now this lavalamp works very well.

Thanks again and have lavalampfull dreams

Pascal

From: Martin.Schmidt-Amelunxen+AT+t-online.de

	Date: 	Sat, 16 Jun 2001 07:22:11 +0200

Hallo an den Macher der Lava Lampen Seite, ich habe ich mit Kollegen mal die Lavamasse untersucht (aus einer OBI Lampe). Ein Mix aus Paraffinwachsen (10 - 15 %), Alkylbenzol (35 - 45 %) und Chlorparaffin (40 - 50 %).

Aus solchen Rohstoffen habe ich dann auch eine Lavalampe gebastelt.

Als Anlage ein Photo vom Ergebnis. Sie funktioniert nun seit über einem Jahr tadellos. Nur der Effekt am Anfang, wenn die Wachsbäumchen erstarren, funktioniert noch nicht zufriedenstellend. Der Lampenfuß besteht aus einer geschliffenen Dose lösl. Cappucchino vom Aldi, der Aufsatz aus einer geschliffenen Dose Knabbererdnüsse (auch Aldi). Die Kappe ist aus einer aufgeschnittenen und geschliffenen Red Bull Büchse gemacht. Glühbirne: 40 Watt Reflektor. Gefärbt habe ich die Lavamasse mit Sudanorange. Dieser Farbstoff ist fantastisch lichtecht.

Gruß
Martin

From: "Marco" <mazon+AT+web.de>

	Date: 	Wed, 31 Mar 1999 21:35:01 +0200
	Subject: Lavalamp

Kochsalz enthält als Trennmittel meist einige schlechtlösliche Stoffe (Calciumcarbonat). Da diese möglicheweise den Ionentauscher einer Geschirrspülmaschine zerstören würden, sind. In Geschirrspülmaschinensalz keine solchen Stoffe enthalten. Solche Salzlösungen lassen sich schnell ohne Trübungen herstellen

Marco Nicolai

(Danke für die Tipps auf deiner Seite)

Last modified: Sat Sep 13 18:14:11 CEST 2003